A source of systematic bias in self-reported physical activity: The cutpoint bias hypothesis

Tim S. Olds, Sjaan R. Gomersall, Spencer T. Olds, Kate Ridley

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    15 Citations (Scopus)


    Objectives: Estimates of adults’ moderate-to-vigorous physical activity (MVPA) based on self-report are generally higher than estimates derived from criterion measures. This study examines a possible explanation for part of this discrepancy: the cutpoint bias hypothesis. This hypothesis proposes that inter- and intra-individual variability in energy expenditure, combined with the fact that adults perform a high proportion of daily activities at or just above the traditional 3 MET cutpoint, result in systematic over-estimates of MVPA.

    Design: Cross-sectional. Methods: Time-use recalls (n = 6862) were collected using the Multimedia Activity Recall for Children and Adults from 2210 adults (1215 female, age 16–93 years) from 16 studies conducted in Australia and New Zealand between 2008-2017. Minutes spent in MVPA were estimated using models with varying levels of intra- and inter-individual (total variability) Unadjusted (0% total variability), Low (11.9%), Best Guess (20.7%), and High (30.0%).

    Results: In the Unadjusted model, participants accumulated an average of 129 (standard deviation 127) min/day of MVPA. Estimated MVPA was 98 (110), 99 (107) and 108 (107) min/day in the Low, Best Guess and High variability models, respectively, with intra-class correlation coefficients with the Unadjusted model ranging from 0.78 to 0.83. Conclusions: These findings support the hypothesis of a cutpoint bias, which probably contributes to the large disparities seen between self-reported and criterion measures of MVPA. Future studies are needed to confirm these findings using other self-report instruments and in other populations.

    Original languageEnglish
    Pages (from-to)924-928
    Number of pages5
    JournalJournal of Science and Medicine in Sport
    Issue number8
    Early online date20 Mar 2019
    Publication statusPublished - Aug 2019


    • Accelerometry
    • Methods
    • Physical activity
    • Sedentary behavior
    • Self-report
    • Use of time


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