Objective: This study examined the effects of consistency tendency on the predictive power of the theory of planned behavior (TPB) in relation to physical activity behavior.

Methods: In this randomized controlled cross-over trial, we recruited 770 undergraduate students from Indonesia who were randomly assigned into two groups. Participants completed physical activity versions of TPB measures at T1 (baseline) and T2 (post 1 week), and the International Physical Activity Questionnaire at T3 (post 1 month). At T1 and T2, the TPB questions were either presented in ensemble-order (i.e., consistency tendency supressed) or alternate-order (i.e., consistency tendency facilitated).

Results: The parameter estimates of the model (CFI > .92, TLI > .90, SRMR < .08, RMSEA < .08) aligned with the tenets of TPB. As compared to ensemble-order, a TPB measured in alternate-order yielded stronger cross-sectional relationships, but this pattern did not appear in the prospective relationships in TPB (i.e., intention/perceived behavioral control and behavior).

Conclusions: Consistency tendency inflated the factor correlations of cross-sectionally measured TPB variables, but the inflation was not observed in the prospective prediction of behavior. Health psychology questionnaires with items presented in ensemble order may represent a viable means of reducing the confounding effect of consistency tendency. © 2019 Informa UK Limited, trading as Taylor & Francis Group.