title: Understanding usage of a hybrid website and smartphone app for weight management: a mixed-methods study.
abstract: BACKGROUND
  Advancements in mobile phone technology offer huge potential for enhancing the timely delivery of health behavior change interventions. The development of smartphone-based health interventions (apps) is a rapidly growing field of research, yet there have been few longitudinal examinations of how people experience and use these apps within their day-to-day routines, particularly within the context of a hybrid Web- and app-based intervention.
  
  
  OBJECTIVE
  This study used an in-depth mixed-methods design to examine individual variation in (1) impact on self-reported goal engagement (ie, motivation, self-efficacy, awareness, effort, achievement) of access to a weight management app (POWeR Tracker) when provided alongside a Web-based weight management intervention (POWeR) and (2) usage and views of POWeR Tracker.
  
  
  METHODS
  Thirteen adults were provided access to POWeR and were monitored over a 4-week period. Access to POWeR Tracker was provided in 2 alternate weeks (ie, weeks 1 and 3 or weeks 2 and 4). Participants' goal engagement was measured daily via self-report. Mixed effects models were used to examine change in goal engagement between the weeks when POWeR Tracker was and was not available and whether the extent of change in goal engagement varied between individual participants. Usage of POWeR and POWeR Tracker was automatically recorded for each participant. Telephone interviews were conducted and analyzed using inductive thematic analysis to further explore participants' experiences using POWeR and POWeR Tracker.
  
  
  RESULTS
  Access to POWeR Tracker was associated with a significant increase in participants' awareness of their eating (β1=0.31, P=.04) and physical activity goals (β1=0.28, P=.03). The level of increase varied between individual participants. Usage data showed that participants used the POWeR website for similar amounts of time during the weeks when POWeR Tracker was (mean 29 minutes, SD 31 minutes) and was not available (mean 27 minutes, SD 33 minutes). POWeR Tracker was mostly accessed in short bursts (mean 3 minutes, SD 2 minutes) during convenient moments or moments when participants deemed the intervention content most relevant. The qualitative data indicated that nearly all participants agreed that it was more convenient to access information on-the-go via their mobiles compared to a computer. However, participants varied in their views and usage of the Web- versus app-based components and the informational versus tracking tools provided by POWeR Tracker.
  
  
  CONCLUSIONS
  This study provides evidence that smartphones have the potential to improve individuals' engagement with their health-related goals when used as a supplement to an existing online intervention. The perceived convenience of mobile access to information does not appear to deter use of Web-based interventions or strengthen the impact of app access on goal engagement. A mixed-methods design enabled exploration of individual variation in daily usage of the app-based tools.
authors.affiliation: Centre for Applications of Health Psychology, Academic Unit of Psychology, University of Southampton, Southampton, United Kingdom. l.morrison@soton.ac.uk.
authors.forename: Leanne G
authors.identifier: http://orcid.org/0000-0002-9961-551X
authors.initials: LG
authors.lastname: Morrison
authors.forename: Charlie
authors.identifier: http://orcid.org/0000-0002-5067-5941
authors.initials: C
authors.lastname: Hargood
authors.forename: Sharon Xiaowen
authors.identifier: http://orcid.org/0000-0002-7923-3979
authors.initials: SX
authors.lastname: Lin
authors.forename: Laura
authors.identifier: http://orcid.org/0000-0003-0122-6610
authors.initials: L
authors.lastname: Dennison
authors.forename: Judith
authors.identifier: http://orcid.org/0000-0002-0835-882X
authors.initials: J
authors.lastname: Joseph
authors.forename: Stephanie
authors.identifier: http://orcid.org/0000-0003-4801-8245
authors.initials: S
authors.lastname: Hughes
authors.forename: Danius T
authors.identifier: http://orcid.org/0000-0001-5430-3267
authors.initials: DT
authors.lastname: Michaelides
authors.forename: Derek
authors.identifier: http://orcid.org/0000-0003-3357-4011
authors.initials: D
authors.lastname: Johnston
authors.forename: Marie
authors.identifier: http://orcid.org/0000-0003-0124-4827
authors.initials: M
authors.lastname: Johnston
authors.forename: Susan
authors.identifier: http://orcid.org/0000-0003-0063-6378
authors.initials: S
authors.lastname: Michie
authors.forename: Paul
authors.identifier: http://orcid.org/0000-0003-3664-1873
authors.initials: P
authors.lastname: Little
authors.forename: Peter Wf
authors.identifier: http://orcid.org/0000-0003-4423-5410
authors.initials: PW
authors.lastname: Smith
authors.forename: Mark J
authors.identifier: http://orcid.org/0000-0001-6251-8786
authors.initials: MJ
authors.lastname: Weal
authors.forename: Lucy
authors.identifier: http://orcid.org/0000-0002-3853-883X
authors.initials: L
authors.lastname: Yardley
mesh_terms: D000293:Adolescent; D000328:Adult; D001835:Body Weight / Q000502:physiology*; D040421:Cell Phone; D003194:Computer-Assisted Instruction / Q000379:methods; D005260:Female; D015438:Health Behavior; D006266:Health Education / Q000379:methods; D006801:Humans; D020407:Internet; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic; D020377:Self Efficacy; D057566:Self Report; D061217:Weight Reduction Programs / Q000379:methods*; D055815:Young Adult
keywords: Internet; behavior; behavioral research; health; mixed-methods; mobile apps; program acceptability; qualitative research; weight loss