Measurement of self-monitoring web technology acceptance and use in an e-health weight-loss trial

Research on technology acceptance and use in e-health weight-loss interventions is limited. Using data from a randomized controlled trial of two e-health interventions, we evaluated the acceptance and use of a self-monitoring Web site for weight loss.

We examined eight theoretical constructs about technology acceptance using adapted 5-point Likert scales and the association of measured Web site usage and weight loss.

All scales had high internal consistency (Cronbach's alpha=0.74-0.97) in both interventions and at 3 and 15 months (end of intensive and maintenance intervention, respectively). From 3 to 15 months mean scores changed unfavorably for two constructs (compatibility and behavioral intention) among coach-led intervention participants, who received ongoing feedback on their self-monitoring entries. Among self-directed intervention participants, who received minimal coach support, mean scores changed unfavorably for five constructs (usefulness, ease of use, concern, compatibility, and behavioral intention). At 3 months, usefulness, ease of use, effect, compatibility, and behavioral intention in the coach-led group (Pearson r=0.33-0.5) and usefulness and affect in the self-directed group (r=0.43-0.46) were significantly correlated with Web site usage, which was correlated with weight loss (β=-0.02, p≤0.001 for both interventions). From 3 to 15 months, mean score changes for usefulness and behavioral intention correlated significantly with Web site usage in the coach-led group.

The adapted acceptance measures showed acceptable psychometric properties and significant associations with actual Web site use, which correlated with weight loss. Better understanding of technology acceptance and use in e-health weight-loss interventions may improve participant adherence and outcome.