title: A Guided Online and Mobile Self-Help Program for Individuals With Eating Disorders: An Iterative Engagement and Usability Study.
abstract: BACKGROUND
  Numerous digital health interventions have been developed for mental health promotion and intervention, including eating disorders. Efficacy of many interventions has been evaluated, yet knowledge about reasons for dropout and poor adherence is scarce. Most digital health intervention studies lack appropriate research design and methods to investigate individual engagement issues. User engagement and program usability are inextricably linked, making usability studies vital in understanding and improving engagement.
  
  
  OBJECTIVE
  The aim of this study was to explore engagement and corresponding usability issues of the Healthy Body Image Program-a guided online intervention for individuals with body image concerns or eating disorders. The secondary aim was to demonstrate the value of usability research in order to investigate engagement.
  
  
  METHODS
  We conducted an iterative usability study based on a mixed-methods approach, combining cognitive and semistructured interviews as well as questionnaires, prior to program launch. Two separate rounds of usability studies were completed, testing a total of 9 potential users. Thematic analysis and descriptive statistics were used to analyze the think-aloud tasks, interviews, and questionnaires.
  
  
  RESULTS
  Participants were satisfied with the overall usability of the program. The average usability score was 77.5/100 for the first test round and improved to 83.1/100 after applying modifications for the second iteration. The analysis of the qualitative data revealed five central themes: layout, navigation, content, support, and engagement conditions. The first three themes highlight usability aspects of the program, while the latter two highlight engagement issues. An easy-to-use format, clear wording, the nature of guidance, and opportunity for interactivity were important issues related to usability. The coach support, time investment, and severity of users' symptoms, the program's features and effectiveness, trust, anonymity, and affordability were relevant to engagement.
  
  
  CONCLUSIONS
  This study identified salient usability and engagement features associated with participant motivation to use the Healthy Body Image Program and ultimately helped improve the program prior to its implementation. This research demonstrates that improvements in usability and engagement can be achieved by testing and adjusting intervention design and content prior to program launch. The results are consistent with related research and reinforce the need for further research to identify usage patterns and effective means for reducing dropout. Digital health research should include usability studies prior to efficacy trials to help create more user-friendly programs that have a higher likelihood of "real-world" adoption.
authors.affiliation: Ferdinand Porsche Distance Learning University of Applied Sciences, Vienna, Austria. martina.nitsch@fernfh.ac.at.
authors.forename: Martina
authors.identifier: http://orcid.org/0000-0003-1149-3376
authors.initials: M
authors.lastname: Nitsch
authors.forename: Christina N
authors.identifier: http://orcid.org/0000-0002-3861-8055
authors.initials: CN
authors.lastname: Dimopoulos
authors.forename: Edith
authors.identifier: http://orcid.org/0000-0002-5013-2285
authors.initials: E
authors.lastname: Flaschberger
authors.forename: Kristina
authors.identifier: http://orcid.org/0000-0003-0716-2232
authors.initials: K
authors.lastname: Saffran
authors.forename: Jenna F
authors.identifier: http://orcid.org/0000-0002-5668-5235
authors.initials: JF
authors.lastname: Kruger
authors.forename: Lindsay
authors.identifier: http://orcid.org/0000-0001-7562-8538
authors.initials: L
authors.lastname: Garlock
authors.forename: Denise E
authors.identifier: http://orcid.org/0000-0002-3599-8689
authors.initials: DE
authors.lastname: Wilfley
authors.forename: Craig B
authors.identifier: http://orcid.org/0000-0002-4564-6548
authors.initials: CB
authors.lastname: Taylor
authors.forename: Megan
authors.identifier: http://orcid.org/0000-0002-0514-5888
authors.initials: M
authors.lastname: Jones
mesh_terms: D001828:Body Image; D001068:Feeding and Eating Disorders / Q000523:psychology / Q000628:therapy*; D006293:Health Promotion / Q000379:methods*; D006801:Humans; D020407:Internet; D007407:Interviews as Topic; D063731:Mobile Applications; D009042:Motivation; D012648:Self Care; D011795:Surveys and Questionnaires; D017216:Telemedicine
keywords: adherence; digital health intervention; dropout; eating disorder; engagement; mobile application; online program; self-help; usability study