Preference for behavior change strategies in randomized controlled trials: Evidence from weight management

Randomized controlled trial participants are expected to embrace assignment to any of the study arms, yet individuals' relative preference for the study arms invariably affects who participates in trials and for how long.

Our ongoing Avoid/Resist trial (1R01DK130851) tests two strategies to bridge the intention-behavior gap in a weight management intervention. Avoid combines pantry makeover and online grocery shopping. Resist involves gamified, inhibitory control training. During screening, individuals rate Avoid and Resist on affective valence (I don't like this - I like this) and instrumental utility (This will not benefit me - This will benefit me) using a 0-100 analogue scale. K-means clustering was used to identify clusters of individuals based on their liking and perceived benefits of the tested strategies before randomization.

Among respondents who completed the screener between January 2024 and January 2025 (n = 306; 64 % Female; 40 % Hispanic/Latino), the correlations between liking and perceived benefit ratings were high (>0.70). Median scores of liking and perceived benefits were 90 and 88 for Resist, and 91.5 and 90 for Avoid. K-means clustering revealed 3 groups: (1) highly favorable to Avoid and Resist (all ratings >90; 61 %); (2) relative preference for Resist (22 %); (3) relative preference for Avoid (17 %).

Even among individuals willing to be randomized, nearly 40 % had a relative preference for one of the study arms. Additional work is needed to understand the role of relative preference on retention, adherence, and outcomes in weight management trials.

The study is registered with ClinicalTrials.gov (NCT05143931).