Measurement · Physical activity
The questionnaire used for global activity surveillance does not measure sitting
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Short answer
GPAQ moderately tracked moderate-to-vigorous activity and its change, and failed to track sedentary time or change in sitting.
What happened
Cleland and colleagues recruited 101 adults stratified by GPAQ activity level and sex, had them wear an Actigraph GT3X for seven days and complete the GPAQ on day 7, then repeated the protocol three to six months later in a subsample. Ninety-five completed baseline. Moderate-to-vigorous activity agreed at r = 0.48 with a mean difference of −0.8 minutes per day, with over-reporting concentrated among the most active. Sedentary behaviour agreed at r = 0.19, with a mean difference of +348.7 minutes per day. Change in activity correlated at r = 0.52; change in sitting did not (r = −0.024).
Why it matters
The GPAQ is used in national surveillance and in the datasets that support sedentary-behaviour guidance. An instrument that tracks activity moderately and sitting not at all cannot support both kinds of claim, and the change results matter more than the cross-sectional ones: an instrument that cannot detect change cannot evaluate an intervention.
Evidence
- Study type
- Criterion validity study against seven-day accelerometry, with a repeat protocol for change
- Sample
- 95 adults at baseline (mean age 44); 41 in the change subsample
- Journal
- BMC Public Health · peer reviewed
- Replication
- Not assessed in this corpus; poor self-report validity for sitting is reported elsewhere in the measurement literature
- Limitations
- One Northern Ireland sample. The change analysis was underpowered at n = 41, and hip accelerometry itself misses posture, so the sedentary comparison is imperfect on both sides.
What this connects to
Sources
The one study this explanation is built from, by the role each plays. Every source links to PaperFren’s explanation of it and to the original paper.
Primary study
- Does the WHO GPAQ match a wearable for activity and sitting?
In 95 adults, GPAQ moderately matched Actigraph MVPA (r=0.48) but poorly captured sitting time (r=0.19), with a 349 min/day sedentary gap.
What it does not showLimitations
A 95-person Northern Ireland sample cannot prove GPAQ works in every country; change n=41 was underpowered, and self-report still misses posture-level sitting.
PaperFren explanationStudy with cards and a quizOriginal paper (DOI)cc by
Before
The GPAQ was applied as a single instrument covering both physical activity and sedentary behaviour across surveillance and intervention studies.
Now
Its two domains have very different validity, and only the activity domain tracks change. A 95-person Northern Ireland sample cannot establish performance in every country, and the change analysis with n = 41 was underpowered.