Health Research Using Facebook to Identify and Recruit Pregnant Women Who Use Electronic Cigarettes: Internet-Based Nonrandomized Pilot Study

Background Participant recruitment is often a challenge, particularly enrolling individuals with relatively rare characteristics. The wide reach of social media may provide a mechanism to overcome these challenges. Objective This paper aimed to provide information to researchers who seek to recruit participants from rare populations using social media for studies with demanding protocols. We aimed to describe a pilot study protocol that identified and enrolled pregnant women (second or third trimester) who were exclusive users of electronic cigarettes (e-cigarettes). We have described the recruitment methods, time, and cost; examined advertisement types that were more or less successful; discussed participant retention and relationship management; and described the process of collecting biological data. Methods In an open-access, nonrandomized pilot study, we placed Facebook advertisements that were selectively targeting women who were likely to be pregnant and interested in e-cigarettes or vaping. The advertisements invited individuals to complete a fully automated eligibility screener based on Qualtrics. Eligible participants were asked to (1) complete a Web-based survey that collected detailed information on the use of e-cigarettes, including the exact type of device and electronic liquid, (2) report the frequency and intensity of e-cigarette use for 3 months before pregnancy and during each trimester, and (3) provide a saliva specimen for a nicotine biomarker assay. We collected a photograph of each participant’s e-cigarette device, 8 weeks after the mother’s due date, to allow corroboration of the self-report and the baby’s birth weight and gestational age from the participant’s physician. Results Participants were recruited between August 19 and October 26, 2017. We enrolled 20 participants in 2 months at a cost of US $3421.28. Baseline data were collected for all 20 participants. Of the 20 women enrolled, 16 provided a saliva sample, 4 provided a photo of the e-cigarette device, and 10 provided physician contact information. Of the 10 physicians contacted by mail, 6 responded with information on the participants and their babies. Conclusions Study findings suggest that Facebook’s targeting criteria should focus on e-cigarette users to maximize advertisement exposure of potentially eligible women. In addition, saliva sample collection was feasible among pregnant women (second or third trimester) who were exclusive e-cigarette users, but obtaining photographs and physician reports was problematic and called for further refinement. These lessons are likely useful to others who are seeking to use social media to recruit participants from rare populations into studies with demanding protocols.

Approx. Percentage of Users (starters) still using the app as recommended after 3 months * n/a Is this a full powered effectiveness trial or a pilot/feasibility trial? * Manuscript tracking number * If this is a JMIR submission, please provide the manuscript tracking number under "other" (The ms tracking number can be found in the submission acknowledgement email, or when you login as author in JMIR. If the paper is already published in JMIR, then the ms tracking number is the four-digit number at the end of the DOI, to be found at the bottom of each published article in JMIR) TITLE AND ABSTRACT 1a) TITLE: Identi cation as a randomized trial in the title yes Other: subitem not at all important 1 2 3 4 5 essential 1a) Does your paper address CONSORT item 1a? * I.e does the title contain the phrase "Randomized Controlled Trial"? (if not, explain the reason under "other") 1a-i) Identify the mode of delivery in the title Identify the mode of delivery. Preferably use "web-based" and/or "mobile" and/or "electronic game" in the title. Avoid ambiguous terms like "online", "virtual", "interactive". Use "Internet-based" only if Intervention includes non-web-based Internet components (e.g. email), use "computer-based" or "electronic" only if o ine products are used. Use "virtual" only in the context of "virtual reality" (3-D worlds). Use "online" only in the context of "online support groups". Complement or substitute product names with broader terms for the class of products (such as "mobile" or "smart phone" instead of "iphone"), especially if the application runs on different platforms.
Does your paper address subitem 1a-i? * Copy and paste relevant sections from manuscript title (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "Internet-based", "Health Research Using Facebook " 1a-ii) Non-web-based components or important co-interventions in title Mention non-web-based components or important co-interventions in title, if any (e.g., "with telephone support").
Does your paper address subitem 1a-ii?
Copy and paste relevant sections from manuscript title (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study n/a 1a-iii) Primary condition or target group in the title Mention primary condition or target group in the title, if any (e.g., "for children with Type I Diabetes") Example: A Web-based and Mobile Intervention with Telephone Support for Children with Type I Diabetes: Randomized Controlled Trial Does your paper address subitem 1a-iii? * Copy and paste relevant sections from manuscript title (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "Pregnant Women who Use E-cigarettes" 1b-i) Key features/functionalities/components of the intervention and comparator in the METHODS section of the ABSTRACT Mention key features/functionalities/components of the intervention and comparator in the abstract. If possible, also mention theories and principles used for designing the site. Keep in mind the needs of systematic reviewers and indexers by including important synonyms. (Note: Only report in the abstract what the main paper is reporting. If this information is missing from the main body of text, consider adding it) Does your paper address subitem 1b-i? * Copy and paste relevant sections from the manuscript abstract (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "The primary aim of the paper is to provide information to researchers who seek to recruit participants from rare populations using social media for studies with rather demanding protocols. We describe a pilot study protocol that identi ed and enrolled currently pregnant women (second or third trimester) who were exclusive electronic cigarette (e-cigarette) users. We describe the recruitment methods, time, and cost; examine advertisement types that were more or less successful; discuss participant retention and relationship management; and describe the process of collecting biological data" 1b-ii) Level of human involvement in the METHODS section of the ABSTRACT Clarify the level of human involvement in the abstract, e.g., use phrases like "fully automated" vs. "therapist/nurse/care provider/physician-assisted" (mention number and expertise of providers involved, if any). (Note: Only report in the abstract what the main paper is reporting. If this information is missing from the main body of text, consider adding it) Copy and paste relevant sections from the manuscript abstract (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "The advertisements invited individuals to complete a fully automated eligibility screener based on Qualtrics. " 1b-iii) Open vs. closed, web-based (self-assessment) vs. face-toface assessments in the METHODS section of the ABSTRACT Mention how participants were recruited (online vs. o ine), e.g., from an open access website or from a clinic or a closed online user group (closed usergroup trial), and clarify if this was a purely web-based trial, or there were face-to-face components (as part of the intervention or for assessment). Clearly say if outcomes were self-assessed through questionnaires (as common in web-based trials Does your paper address subitem 1b-iii? Copy and paste relevant sections from the manuscript abstract (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "In an open access non-randomized pilot study, we placed Facebook advertisements selectively targeting women who were likely to be pregnant and interested in ecigarettes or vaping. " 1b-iv) RESULTS section in abstract must contain use data Report number of participants enrolled/assessed in each group, the use/uptake of the intervention (e.g., attrition/adherence metrics, use over time, number of logins etc.), in addition to primary/secondary outcomes. (Note: Only report in the abstract what the main paper is reporting. If this information is missing from the main body of text, consider adding it)

INTRODUCTION 2a) In INTRODUCTION: Scienti c background and explanation of rationale
Does your paper address subitem 1b-iv?
Copy and paste relevant sections from the manuscript abstract (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "We enrolled 20 participants in two months at a cost of $3421.28 USD. Baseline data was collected for all 20 participants. Of the 20 women enrolled, 16 provided a saliva sample, 4 provided a photo of the e-cigarette device, and 10 provided physician contact information. Of the 10 physicians contacted by mail, 6 responded with information on the participants and their babies." 1b-v) CONCLUSIONS/DISCUSSION in abstract for negative trials Conclusions/Discussions in abstract for negative trials: Discuss the primary outcome -if the trial is negative (primary outcome not changed), and the intervention was not used, discuss whether negative results are attributable to lack of uptake and discuss reasons. (Note: Only report in the abstract what the main paper is reporting. If this information is missing from the main body of text, consider adding it) Does your paper address subitem 1b-v?
Copy and paste relevant sections from the manuscript abstract (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study n/a; this was not a negative trial. Describe the problem and the type of system/solution that is object of the study: intended as standalone intervention vs. incorporated in broader health care program? Intended for a particular patient population? Goals of the intervention, e.g., being more cost-effective to other interventions, replace or complement other solutions? (Note: Details about the intervention are provided in "Methods" under 5) Does your paper address subitem 2a-i? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "Participant recruitment is frequently a challenge in public health research, particularly when the study aims to enroll those who are di cult to reach or recruit into research studies [1,2]. The population of interest may be rare among the overall population (e.g., cystic brosis, Huntington disease, or Duchenne muscular dystrophy), di cult to identify or contact (e.g., sex workers), or hesitant to participate due to stigma or legality (e.g., people with substance use disorders, abuse victims, or illegal immigrants) [3][4][5]. To obtain a su cient number of hard-toreach participants, a researcher could conduct multi-center trials, but this can be quite expensive. One approach that has been increasingly used to address this challenge is to utilize social media to recruit from the larger population. " Does your paper address CONSORT subitem 2b? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "Thus, the purpose of present study was to examine the utility of Facebook to recruit pregnant women who used e-cigarettes into a study with a protocol that required acquisition of saliva samples, extensive surveys assessing details of e-cigarette use (20-30 minutes), photographs of the e-cigarette device, and physician corroboration regarding the pregnancy and infant." 3a) Description of trial design (such as parallel, factorial) including allocation ratio 3b) Important changes to methods after trial commencement (such as eligibility criteria), with reasons subitem not at all important 1 2 3 4 5 essential Does your paper address CONSORT subitem 3a? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "The present study was open access (i.e., participants self-enroll) non-randomized pilot study." Does your paper address CONSORT subitem 3b? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study There were no important changes to methods after trial commencement .

3b-i) Bug xes, Downtimes, Content Changes
Bug xes, Downtimes, Content Changes: ehealth systems are often dynamic systems. A description of changes to methods therefore also includes important changes made on the intervention or comparator during the trial (e.g., major bug xes or changes in the functionality or content) (5-iii) and other "unexpected events" that may have in uenced study design such as staff Does your paper address subitem 3b-i?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "We rst used a "conversion tracking" advertisement and later used a "tra c tracking" advertisement [14,15]. While both methods use Facebook pixel to gather information from Facebook users, they target slightly different groups. Conversion tracking gathers information from only those who end up at the nal webpage (e.g., those who purchase an item, sign up for a study, or provide contact information). On the other hand, tra c tracking gathers information from those who click through the processes (e.g., an advertisement, screener, study explanation, or baseline questionnaire)." Does your paper address CONSORT subitem 4a? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "The advertisement invited them to complete an online eligibility-screening questionnaire. Inclusion criteria for this study were as follows: 1) pregnant women who were in their 2nd or 3rd trimester, 2) age 18-50, 3) currently non-smoker of tobacco, 4) e-cigarette user (≥5 days per week). "

4a-i) Computer / Internet literacy
Computer / Internet literacy is often an implicit "de facto" eligibility criterion -this should be explicitly clari ed. subitem not at all important 1 2 3 4 5 essential Does your paper address subitem 4a-i?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "The enrolled participants likely had high literacy level considering that 65% of the participants were at least 'some college' or above." "In addition, the requirements to read the consent form online and complete questionnaires online suggest that a relatively high literacy level, as well as high "Internet literacy", would be required for participation. " 4a-ii) Open vs. closed, web-based vs. face-to-face assessments: Open vs. closed, web-based vs. face-to-face assessments: Mention how participants were recruited (online vs. o ine), e.g., from an open access website or from a clinic, and clarify if this was a purely web-based trial, or there were face-to-face components (as part of the intervention or for assessment), i.e., to what degree got the study team to know the participant. In online-only trials, clarify if participants were quasi-anonymous and whether having multiple identities was possible or whether technical or logistical measures (e.g., cookies, email con rmation, phone calls) were used to detect/prevent these.
Does your paper address subitem 4a-ii? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "The present study was open access (i.e., participants self-enroll) non-randomized pilot study." "With respect to human involvement, advertisement, screening, and enrollment into the study was purely web-based, and once enrolled, research assistant contacted the participants only via email and there were no on-site visits." subitem not at all important 1 2 3 4 5 essential 4b) Settings and locations where the data were collected 4a-iii) Information giving during recruitment Information given during recruitment. Specify how participants were briefed for recruitment and in the informed consent procedures (e.g., publish the informed consent documentation as appendix, see also item X26), as this information may have an effect on user self-selection, user expectation and may also bias results.
Does your paper address subitem 4a-iii?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "Safety and security procedures were elaborated in the informed consent form, which was collected online via Qualtrics. With respect to harms or unintended effects, we noted the only risk to you of participating would be if personal information about you or your baby reached people other than the researchers. We will be extremely careful to do everything we can to make sure that doesn't happen. Your data will be stored on a computer at Brown University, never on a laptop or memory stick. The data will only be seen by people on the research team who need to work with it or the Brown Institutional Review Board overseeing the study. There are no direct bene ts to you from being in the study. However, you may be contributing to research that will help us provide more accurate information about ecigarettes and health to expectant mothers in the future." Does your paper address CONSORT subitem 4b? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "All surveys were conducted online using the Qualtrics platform [16]. " "With respect to human involvement, advertisement, screening, and enrollment into the study was purely web-based, and once enrolled, research assistant contacted the participants only via email and there were no on-site visits. " 4b-i) Report if outcomes were (self-)assessed through online questionnaires Clearly report if outcomes were (self-)assessed through online questionnaires (as common in webbased trials) or otherwise.
Does your paper address subitem 4b-i? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study ""All surveys were conducted online using the Qualtrics platform [16]. " "With respect to human involvement, advertisement, screening, and enrollment into the study was purely web-based, and once enrolled, research assistant contacted the participants only via email and there were no on-site visits. " 4b-ii) Report how institutional a liations are displayed Report how institutional a liations are displayed to potential participants [on ehealth media], as a liations with prestigious hospitals or universities may affect volunteer rates, use, and reactions with regards to an intervention.(Not a required item -describe only if this may bias results) Does your paper address subitem 4b-ii?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Figure 1 shows Facebook Advertisement title, "Brown University's Expecting Moms Research Study" 5) The interventions for each group with su cient details to allow replication, including how and when they were actually administered subitem not at all important 1 2 3 4 5 essential 5-i) Mention names, credential, a liations of the developers, sponsors, and owners Mention names, credential, a liations of the developers, sponsors, and owners [6] (if authors/evaluators are owners or developer of the software, this needs to be declared in a "Con ict of interest" section or mentioned elsewhere in the manuscript).
Does your paper address subitem 5-i?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study essential 5-ii) Describe the history/development process Describe the history/development process of the application and previous formative evaluations (e.g., focus groups, usability testing), as these will have an impact on adoption/use rates and help with interpreting results.
Does your paper address subitem 5-ii?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "Nascent literature on recruitment of e-cigarette users using social media (e.g., Facebook and Twitter), conducted by our team [11] and other [12], has shown promising results."

5-iii) Revisions and updating
Revisions and updating. Clearly mention the date and/or version number of the application/intervention (and comparator, if applicable) evaluated, or describe whether the intervention underwent major changes during the evaluation process, or whether the development and/or content was "frozen" during the trial. Describe dynamic components such as news feeds or changing content which may have an impact on the replicability of the intervention (for unexpected events see item 3b).
Does your paper address subitem 5-iii?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study These aspects were detailed in Table 1 and 2. Does your paper address subitem 5-iv?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "Among 36 participants, research staff excluded 16 participants (44%) who appeared to be dishonest in their responses, presumably to collect the incentive. For example, some participants attempted to enroll twice in the study using a different name but the same contact information. One participant claimed that she has not received the Amazon.com incentive after our research team had received an automated message from Amazon.com stating that she had redeemed her gift card.
" 5-v) Ensure replicability by publishing the source code, and/or providing screenshots/screen-capture video, and/or providing owcharts of the algorithms used Ensure replicability by publishing the source code, and/or providing screenshots/screen-capture video, and/or providing owcharts of the algorithms used. Replicability (i.e., other researchers should in principle be able to replicate the study) is a hallmark of scienti c reporting. screening process of the present study is more like a process (i.e., ideal for tra c tracking) than a snapshot decision (i.e., ideal for conversion tracking). An integral metric to determine the cost-effectiveness of conversion vs. tra c is "Cost per results", which can be found in the summary table provided in Facebook Ads Manager. Cost per results counts the number of results (e.g., conversion or tra c) a researcher received based on the settings for the ad. For example, if a researcher selected conversions as their campaign objective, the results metric may show the number of "View contents" that occurred due to someone seeing his or her ad. In the present study, for conversion, the cost per results was "View Contents". For tra c, the cost per result was "Link Clicks" and the cost was signi cantly lower."

5-vi) Digital preservation
Digital preservation: Provide the URL of the application, but as the intervention is likely to change or disappear over the course of the years; also make sure the intervention is archived (Internet Archive, webcitation.org, and/or publishing the source code or screenshots/videos alongside the article). As pages behind login screens cannot be archived, consider creating demo pages which are accessible without login. Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study ""Social recruitment" of study participants using Facebook (business.facebook.com) has gained signi cant traction in recent years [6][7][8]. "

5-vii) Access
Access: Describe how participants accessed the application, in what setting/context, if they had to pay (or were paid) or not, whether they had to be a member of speci c group. If known, describe how participants obtained "access to the platform and Internet" [1]. To ensure access for editors/reviewers/readers, consider to provide a "backdoor" login account or demo mode for reviewers/readers to explore the application (also important for archiving purposes, see vi).
Does your paper address subitem 5-vii? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study ""Social recruitment" of study participants using Facebook ( subitem not at all important 1 2 3 4 5 essential Does your paper address subitem 5-viii? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "One of the advantages of recruiting on Facebook or other social media platforms is that the platform uses a "pixel" code-a short programming script that is placed on an advertiser's website to track tra c conversions from the platform advertisements [13]. The pixel code allows Facebook's algorithm to characterize users who interact with an advertisement (e.g., like, share or directly click the post), and then further disseminate the advertisement to other Facebook users with similar characteristics." "We rst used a "conversion tracking" advertisement and later used a "tra c tracking" advertisement [14,15]. While both methods use Facebook pixel to gather information from Facebook users, they target slightly different groups. Conversion tracking gathers information from only those who end up at the nal webpage (e.g., those who purchase an item, sign up for a study, or provide contact information). On the other hand, tra c tracking gathers information from those who click through the processes (e.g., an advertisement, screener, study explanation, or baseline questionnaire). As an analogy, on a clothing store website, conversion tracking would collect customer information from only those who purchased clothing, whereas tra c tracking would collect customer information from those who did not purchase any clothing but showed signi cant interest in certain items such as viewing it or adding it to their cart. "

5-ix) Describe use parameters
Describe use parameters (e.g., intended "doses" and optimal timing for use). Clarify what instructions or recommendations were given to the user, e.g., regarding timing, frequency, heaviness of use, if any, or was the intervention used ad libitum. subitem not at all important 1 2 3 4 5 essential Does your paper address subitem 5-ix?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "We incrementally ne-tuned our parameters for the subsequent set based on the turnout of the ongoing one. The speci cs of daily budget and audience details were informed by our team's previous research [11]. Ad sets one and two used same search terms, which included "electronic cigarettes", "vapor", and "pregnancy" and enrolled ve participants. Because many people were screening out from Ad set one, we added "baby shower" and "new moms" to the existing search terms in Ad set three and four and enrolled an additional nine participants. This may have in uenced the reduction in per enrollment cost from ~$165 (Ad sets one and two) to ~$150 (Ad sets three and four). In Ad set ve, we increased the daily money spent to $300 (from $200) and enrolled an additional three participants, but this resulted in a higher per enrollment cost of ~$200. In Ad set six, daily money spent was reduced to $150; the number of advertisements within an Ad set was reduced from three to one; and conversion window was reduced to one day from seven days. However, Ad set six enrolled no participants. In Ad set seven, we expanded age restriction from 18-25 to 18-50 but enrolled no additional participants. In Ad set eight, we moved up the conversion to screeners from the nal webpage but this only resulted in enrolling one additional participant."

5-x) Clarify the level of human involvement
Clarify the level of human involvement (care providers or health professionals, also technical assistance) in the e-intervention or as co-intervention (detail number and expertise of professionals involved, if any, as well as "type of assistance offered, the timing and frequency of the support, how it is initiated, and the medium by which the assistance is delivered". It may be necessary to distinguish between the level of human involvement required for the trial, and the level of human involvement required for a routine application outside of a RCT setting (discuss under item 21 -generalizability). Does your paper address subitem 5-x?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "With respect to human involvement, advertisement, screening, and enrollment into the study was purely web-based, and once enrolled, research assistant contacted the participants only via email and there were no on-site visits. " 5-xi) Report any prompts/reminders used Report any prompts/reminders used: Clarify if there were prompts (letters, emails, phone calls, SMS) to use the application, what triggered them, frequency etc. It may be necessary to distinguish between the level of prompts/reminders required for the trial, and the level of prompts/reminders for a routine application outside of a RCT setting (discuss under item 21 -generalizability).
Does your paper address subitem 5-xi? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "The Facebook advertising tool placed messages in their feed selectively to target women who were likely to be pregnant and interested in e-cigarettes or vaping."

5-xii) Describe any co-interventions (incl. training/support)
Describe any co-interventions (incl. training/support): Clearly state any interventions that are provided in addition to the targeted eHealth intervention, as ehealth intervention may not be designed as standalone intervention. This includes training sessions and support [1]. It may be necessary to distinguish between the level of training required for the trial, and the level of training for a routine application outside of a RCT setting (discuss under item 21 -generalizability. 6a) Completely de ned pre-speci ed primary and secondary outcome measures, including how and when they were assessed Does your paper address subitem 5-xii? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study There were no co-intervention.
Does your paper address CONSORT subitem 6a? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "An integral metric to determine the cost-effectiveness of conversion vs. tra c is "Cost per results", which can be found in the summary table provided in Facebook Ads Manager. Cost per results counts the number of results (e.g., conversion or tra c) a researcher received based on the settings for the ad. For example, if a researcher selected conversions as their campaign objective, the results metric may show the number of "View contents" that occurred due to someone seeing his or her ad. In the present study, for conversion, the cost per results was "View Contents".
For tra c, the cost per result was "Link Clicks" and the cost was signi cantly lower." "The survey instrument collected detailed information on (1) the exact type of ecigarette device and e-liquid used, (2) the frequency and intensity of use for the 3 months before pregnancy and during each trimester of pregnancy. Eight weeks after the baby's due date, we requested a photograph of each participant's e-cigarette device to allow corroboration of self-report, and the baby's birthweight and gestational age from the mother's physician." Does your paper address subitem 6a-i?
Copy and paste relevant sections from manuscript text "Eight weeks after the mother's due date, we collected a photograph of each participant's e-cigarette device to allow corroboration of self-report and the baby's birth weight and gestational age from the participant's physician." 6a-ii) Describe whether and how "use" (including intensity of use/dosage) was de ned/measured/monitored Describe whether and how "use" (including intensity of use/dosage) was de ned/measured/monitored (logins, log le analysis, etc.). Use/adoption metrics are important process outcomes that should be reported in any ehealth trial. researcher selected conversions as their campaign objective, the results metric may show the number of "View contents" that occurred due to someone seeing his or her ad. In the present study, for conversion, the cost per results was "View Contents". For tra c, the cost per result was "Link Clicks" and the cost was signi cantly lower." 6a-iii) Describe whether, how, and when qualitative feedback from participants was obtained Describe whether, how, and when qualitative feedback from participants was obtained (e.g., through emails, feedback forms, interviews, focus groups).
Does your paper address subitem 6a-iii?
Copy and paste relevant sections from manuscript text "Negative postings may in uence the recruitment process since prospective respondents can see the unfavorable comments and might avoid the advertisement. We responded to negative comments from a Facebook user who later enrolled in the study. This user posted a comment on one of the advertisements in the Ad set three Does your paper address CONSORT subitem 6b? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study There were no changes to trial outcomes after the trial commenced.
7a-i) Describe whether and how expected attrition was taken into account when calculating the sample size Describe whether and how expected attrition was taken into account when calculating the sample size.
Does your paper address subitem 7a-i?
Copy and paste relevant sections from manuscript title (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "Our initial plan was to enroll 30 participants and determine how many we were able to retain throughout the study." Does your paper address CONSORT subitem 7b? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "The recruitment was ceased after exhausting pre-determined budget allocated for recruitment." 8a) Method used to generate the random allocation sequence NPT: When applicable, how care providers were allocated to each trial group 8b) Type of randomisation; details of any restriction (such as blocking and block size) 9) Mechanism used to implement the random allocation sequence (such as sequentially numbered containers), describing any steps taken to conceal the sequence until interventions were assigned 10) Who generated the random allocation sequence, who enrolled participants, and who assigned participants to interventions Does your paper address CONSORT subitem 8a? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study n/a. The present study was not a randomized controlled trial.
Does your paper address CONSORT subitem 8b? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study n/a. The present study was not a randomized controlled trial.
Does your paper address CONSORT subitem 9? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study n/a. The present study was not a randomized controlled trial.
11a) If done, who was blinded after assignment to interventions (for example, participants, care providers, those assessing outcomes) and how NPT: Whether or not administering co-interventions were blinded to group assignment subitem not at all important 1 2 3 4 5 essential subitem not at all important 1 2 3 4 5 essential Does your paper address CONSORT subitem 10? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study n/a. The present study was not a randomized controlled trial.
11a-i) Specify who was blinded, and who wasn't Specify who was blinded, and who wasn't. Usually, in web-based trials it is not possible to blind the participants [1, 3] (this should be clearly acknowledged), but it may be possible to blind outcome assessors, those doing data analysis or those administering co-interventions (if any).
Does your paper address subitem 11a-i? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study n/a. The present study was not a randomized controlled trial.
11a-ii) Discuss e.g., whether participants knew which intervention was the "intervention of interest" and which one was the "comparator" Informed consent procedures (4a-ii) can create biases and certain expectations -discuss e.g., whether participants knew which intervention was the "intervention of interest" and which one was the "comparator".
11b) If relevant, description of the similarity of interventions (this item is usually not relevant for ehealth trials as it refers to similarity of a placebo or sham intervention to a active medication/intervention) 12a) Statistical methods used to compare groups for primary and secondary outcomes NPT: When applicable, details of whether and how the clustering by care providers or centers was addressed Does your paper address subitem 11a-ii?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study n/a. The present study was not a randomized controlled trial.
Does your paper address CONSORT subitem 11b? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study n/a. The present study was not a randomized controlled trial.
Does your paper address CONSORT subitem 12a? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study n/a. The present study was not a randomized controlled trial. 12a-i) Imputation techniques to deal with attrition / missing values Imputation techniques to deal with attrition / missing values: Not all participants will use the intervention/comparator as intended and attrition is typically high in ehealth trials. Specify how participants who did not use the application or dropped out from the trial were treated in the statistical analysis (a complete case analysis is strongly discouraged, and simple imputation techniques such as LOCF may also be problematic [4]).
Does your paper address subitem 12a-i? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study n/a. The present study was not a randomized controlled trial and we did not perform statistical analyses to quantify a difference.
Does your paper address CONSORT subitem 12b? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study n/a. The present study was not a randomized controlled trial and we did not perform statistical analyses to quantify a difference. Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "Safety and security procedures were elaborated in the informed consent form, which was collected online via Qualtrics. With respect to harms or unintended effects, we noted the only risk to you of participating would be if personal information about you or your baby reached people other than the researchers. We will be extremely careful to do everything we can to make sure that doesn't happen. Your data will be stored on a computer at Brown University, never on a laptop or memory stick. The data will only be seen by people on the research team who need to work with it or the Brown Institutional Review Board overseeing the study. There are no direct bene ts to you from being in the study. However, you may be contributing to research that will help us provide more accurate information about ecigarettes and health to expectant mothers in the future."

X26-iii) Safety and security procedures
Safety and security procedures, incl. privacy considerations, and any steps taken to reduce the likelihood or detection of harm (e.g., education and training, availability of a hotline)

RESULTS
13a) For each group, the numbers of participants who were randomly assigned, received intended treatment, and were analysed for the primary outcome NPT: The number of care providers or centers performing the intervention in each group and the number of patients treated by each care provider in each center 13b) For each group, losses and exclusions after randomisation, together with reasons Does your paper address subitem X26-iii?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "Safety and security procedures were elaborated in the informed consent form, which was collected online via Qualtrics. With respect to harms or unintended effects, we noted the only risk to you of participating would be if personal information about you or your baby reached people other than the researchers. We will be extremely careful to do everything we can to make sure that doesn't happen.
Your data will be stored on a computer at Brown University, never on a laptop or memory stick. The data will only be seen by people on the research team who need to work with it or the Brown Institutional Review Board overseeing the study. There are no direct bene ts to you from being in the study. However, you may be contributing to research that will help us provide more accurate information about ecigarettes and health to expectant mothers in the future." Does your paper address CONSORT subitem 13a? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study n/a. The present study was not a randomized controlled trial and we did not perform statistical analyses to quantify a difference. subitem not at all important 1 2 3 4 5 essential 14a) Dates de ning the periods of recruitment and follow-up Does your paper address CONSORT subitem 13b? (NOTE: Preferably, this is shown in a CONSORT ow diagram) * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study n/a. The present study was not a randomized controlled trial and we did not perform statistical analyses to quantify a difference.

13b-i) Attrition diagram
Strongly recommended: An attrition diagram (e.g., proportion of participants still logging in or using the intervention/comparator in each group plotted over time, similar to a survival curve) or other gures or tables demonstrating usage/dose/engagement.

Does your paper address subitem 13b-i?
Copy and paste relevant sections from the manuscript or cite the gure number if applicable (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "The ow diagram of Facebook advertisement clicks (n=3,891) to nal enrollment (n=20) is illustrated in Figure 2." Does your paper address CONSORT subitem 14a? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study 14a-i) Indicate if critical "secular events" fell into the study period Indicate if critical "secular events" fell into the study period, e.g., signi cant changes in Internet resources available or "changes in computer hardware or Internet delivery resources" Does your paper address subitem 14a-i?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "To our knowledge, there was no critical secular events (e.g., signi cant changes in Internet resources available) during this period." Does your paper address CONSORT subitem 14b? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "The recruitment was ceased after exhausting pre-determined budget allocated for recruitment." Does your paper address CONSORT subitem 15? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "Demographic characteristics of the enrolled participants are shown in Table 3. " In ehealth trials it is particularly important to report demographics associated with digital divide issues, such as age, education, gender, social-economic status, computer/Internet/ehealth literacy of the participants, if known.
Does your paper address subitem 15-i? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "The enrolled participants likely had high literacy level considering that 65% of the participants were at least 'some college' or above." 16-i) Report multiple "denominators" and provide de nitions Report multiple "denominators" and provide de nitions: Report N's (and effect sizes) "across a range of study participation [and use] thresholds" [1], e.g., N exposed, N consented, N used more than x times, N used more than y weeks, N participants "used" the intervention/comparator at speci c pre-de ned time points of interest (in absolute and relative numbers per group). Always clearly de ne "use" of the intervention.

16-ii) Primary analysis should be intent-to-treat
Primary analysis should be intent-to-treat, secondary analyses could include comparing only "users", with the appropriate caveats that this is no longer a randomized sample (see 18-i).
Does your paper address subitem 16-ii?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study n/a. The present study was not a randomized controlled trial and we did not perform statistical analyses to quantify a difference.
17a) For each primary and secondary outcome, results for each group, and the estimated effect size and its precision (such as 95% con dence interval) subitem not at all important 1 2 3 4 5 essential 17b) For binary outcomes, presentation of both absolute and relative effect sizes is recommended Does your paper address CONSORT subitem 17a? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study n/a. The present study was not a randomized controlled trial and we did not perform statistical analyses to quantify a difference.

17a-i) Presentation of process outcomes such as metrics of use and intensity of use
In addition to primary/secondary (clinical) outcomes, the presentation of process outcomes such as metrics of use and intensity of use (dose, exposure) and their operational de nitions is critical. This does not only refer to metrics of attrition (13-b) (often a binary variable), but also to more continuous exposure metrics such as "average session length". These must be accompanied by a technical description how a metric like a "session" is de ned (e.g., timeout after idle time) [1] (report under item 6a).
Does your paper address subitem 17a-i?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study n/a. This was a non-randomized pilot study, which provides information to researchers who seek to recruit participants from rare populations using social media for studies with rather demanding protocols.
18) Results of any other analyses performed, including subgroup analyses and adjusted analyses, distinguishing pre-speci ed from exploratory subitem not at all important 1 2 3 4 5 essential Does your paper address CONSORT subitem 17b? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study n/a. This was a non-randomized pilot study, which provides information to researchers who seek to recruit participants from rare populations using social media for studies with rather demanding protocols. We did not perform statistical analyses.
Does your paper address CONSORT subitem 18? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study n/a. This was a non-randomized pilot study, which provides information to researchers who seek to recruit participants from rare populations using social media for studies with rather demanding protocols. We did not perform statistical analyses.

18-i) Subgroup analysis of comparing only users
A subgroup analysis of comparing only users is not uncommon in ehealth trials, but if done, it must be stressed that this is a self-selected sample and no longer an unbiased sample from a randomized trial (see 16-iii). subitem not at all important 1 2 3 4 5 essential Does your paper address subitem 18-i?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study n/a. This was a non-randomized pilot study, which provides information to researchers who seek to recruit participants from rare populations using social media for studies with rather demanding protocols. We did not perform statistical analyses.
Does your paper address CONSORT subitem 19? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "With respect to harms or unintended effects, we noted the only risk to you of participating would be if personal information about you or your baby reached people other than the researchers. We will be extremely careful to do everything we can to make sure that doesn't happen. Your data will be stored on a computer at Brown University, never on a laptop or memory stick. The data will only be seen by people on the research team who need to work with it or the Brown Institutional Review Board overseeing the study. There are no direct bene ts to you from being in the study. However, you may be contributing to research that will help us provide more accurate information about e-cigarettes and health to expectant mothers in the future."

19-i) Include privacy breaches, technical problems
Include privacy breaches, technical problems. This does not only include physical "harm" to participants, but also incidents such as perceived or real privacy breaches [1], technical problems, and other unexpected/unintended incidents. "Unintended effects" also includes unintended positive effects [2]. Does your paper address subitem 19-ii?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study ""Negative postings may in uence the recruitment process since prospective respondents can see the unfavorable comments and might avoid the advertisement.
We responded to negative comments from a Facebook user who later enrolled in the study. This user posted a comment on one of the advertisements in the Ad set three Restate study questions and summarize the answers suggested by the data, starting with primary outcomes and process outcomes (use).
Does your paper address subitem 22-i? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "Results from this study may help to inform strategies used to recruit pregnant women who use e-cigarettes but not tobacco into a study with a protocol that has multiple, somewhat demanding components. Based on the results of the Facebook advertisements, the speci c lesson learned from the present study regarding identifying rare populations was the importance of targeting criteria." Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "A more integrated survey approach in which users attach the photo directly to the survey may be less burdensome and more successful. " "Each of these components calls for evaluation of the study's burden, nancial incentives, and privacy considerations."

20-i) Typical limitations in ehealth trials
Typical limitations in ehealth trials: Participants in ehealth trials are rarely blinded. Ehealth trials often look at a multiplicity of outcomes, increasing risk for a Type I error. Discuss biases due to non-use of the intervention/usability issues, biases through informed consent procedures, unexpected events. 21) Generalisability (external validity, applicability) of the trial ndings NPT: External validity of the trial ndings according to the intervention, comparators, patients, and care providers or centers involved in the trial subitem not at all important 1 2 3 4 5 essential Does your paper address subitem 20-i? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "It is worth noting possibility of sampling bias such that Facebook users may not be representative of general population. A systematic review of this topic suggest that Facebook-recruited samples were generally representative of samples recruited through traditional methods, except socioeconomic status was higher among Facebook users [19]. Higher socioeconomic status among Facebook users has been also highlighted by a study that examined the representativeness of social media in Great Britain [20]. In addition, the requirements to read the consent form online and complete questionnaires online suggest that a relatively high literacy level, as well as high "Internet literacy", would be required for participation. Taken together, the present study may have recruited those with higher education level than general population. Finally, to the extent of our knowledge, a Facebook Ad user has no insight into Facebook's placement of the ads under either tra c or conversion tracking. As such, it is impossible to evaluate the potential for bias beyond our initial target criteria. As with other types of quota sampling, conversion or tra c tracking strategies monitor the returns as they come in, which allows a researcher to promptly modify the recruitment criteria to optimize the sampling bias."

21-i) Generalizability to other populations
Generalizability to other populations: In particular, discuss generalizability to a general Internet population, outside of a RCT setting, and general patient population, including applicability of the study results for other organizations https://docs.google.com/forms/d/e/1FAIpQLSfZBSUp1bwOc_OimqcS64RdfIAFvmrTSkZQL2-3O8O9hrL5Sw/viewform?hl=en_US&formkey=dGlKd2… 50/54 subitem not at all important 1 2 3 4 5 essential Does your paper address subitem 21-i?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "It is worth noting possibility of sampling bias such that Facebook users may not be representative of general population. A systematic review of this topic suggest that Facebook-recruited samples were generally representative of samples recruited through traditional methods, except socioeconomic status was higher among Facebook users [19]. Higher socioeconomic status among Facebook users has been also highlighted by a study that examined the representativeness of social media in Great Britain [20]. In addition, the requirements to read the consent form online and complete questionnaires online suggest that a relatively high literacy level, as well as high "Internet literacy", would be required for participation. Taken together, the present study may have recruited those with higher education level than general population. Finally, to the extent of our knowledge, a Facebook Ad user has no insight into Facebook's placement of the ads under either tra c or conversion tracking. As such, it is impossible to evaluate the potential for bias beyond our initial target criteria. As with other types of quota sampling, conversion or tra c tracking strategies monitor the returns as they come in, which allows a researcher to promptly modify the recruitment criteria to optimize the sampling bias." 21-ii) Discuss if there were elements in the RCT that would be different in a routine application setting Discuss if there were elements in the RCT that would be different in a routine application setting (e.g., prompts/reminders, more human involvement, training sessions or other co-interventions) and what impact the omission of these elements could have on use, adoption, or outcomes if the intervention is applied outside of a RCT setting.
Does your paper address subitem 21-ii?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study n/a. Does your paper address CONSORT subitem 23? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "The funding for the study was provided by Brown University, Pilot Study of E-Cigarettes and Pregnancy Outcome (#1707001839)." Does your paper address CONSORT subitem 24? * Cite a Multimedia Appendix, other reference, or copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study n/a Does your paper address CONSORT subitem 25? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study In addition to the usual declaration of interests ( nancial or otherwise), also state the relation of the study team towards the system being evaluated, i.e., state if the authors/evaluators are distinct from or identical with the developers/sponsors of the intervention.
Does your paper address subitem X27-i?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "The authors declare that there is no con ict of interest." As a result of using this checklist, did you make changes in your manuscript? * What were the most important changes you made as a result of using this checklist?
As a result of using this checklist, we added information about human involvement. STOP -Save this form as PDF before you click submit To generate a record that you lled in this form, we recommend to generate a PDF of this page (on a Mac, simply select "print" and then select "print as PDF") before you submit it.
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As a result of using this checklist, do you think your manuscript has improved? * Would you like to become involved in the CONSORT EHEALTH group?
This would involve for example becoming involved in participating in a workshop and writing an "Explanation and Elaboration" document Any other comments or questions on CONSORT EHEALTH Your answer