Evaluating the Impact of a Game (Inner Dragon) on User Engagement Within a Leading Smartphone App for Smoking Cessation: Randomized Controlled Trial

Justin S White   ^{1, 2, 3} , PhD ;   Séverine Toussaert   ⁴ , PhD ;   Bethany R Raiff   ⁵ , PhD ;   Marie K Salem   ^{2, 6} , MPH ;   Amy Yunyu Chiang   ² , PhD ;   David Crane   ⁷ , PhD ;   Edward Warrender   ⁷ ;   Courtney R Lyles   ⁸ , PhD ;   Lorien C Abroms   ⁹ , SCD ;   J Lee Westmaas   ^{10 *} , PhD ;   Johannes Thrul   ^{11, 12, 13 *} , PhD

¹ Department of Health Law, Policy and Management, Boston University School of Public Health, Boston, MA, United States

² Philip R Lee Institute for Health Policy Studies, University of California, San Francisco, San Francisco, CA, United States

³ Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, CA, United States

⁴ Department of Economics, University of Oxford, Oxford, United Kingdom

⁵ Department of Psychology, Rowan University, Glassboro, NJ, United States

⁶ Department of Health Policy and Management, Fielding School of Public Health, University of California, Los Angeles, Los Angeles, CA, United States

⁷ 23 Limited, London, United Kingdom

⁸ Department of Public Health Sciences, University of California, Davis, Davis, CA, United States

⁹ Department of Prevention and Community Health, Milken Institute School of Public Health, The George Washington University, Washington, DC, United States

¹⁰ Population Science, American Cancer Society, Atlanta, GA, United States

¹¹ Department of Mental Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States

¹² Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, MD, United States

¹³ Centre for Alcohol Policy Research, La Trobe University, Melbourne, Australia

*these authors contributed equally