1. Response conversion for improving comparability of international physical activity data
- Author
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Hopman-Rock, M., Dusseldorp, E., Chorus, A.M.J., Jacobusse, G.W., Ruetten, A., Van Buuren, S., Methodology and statistics for the behavioural and social sciences, Afd methoden en statistieken, Public and occupational health, EMGO - Musculoskeletal health, Methodology and statistics for the behavioural and social sciences, and Afd methoden en statistieken
- Subjects
Adult ,Male ,Internationality ,Culture ,Motor Activity ,cultural bias ,Cultural bias ,Item response theory ,Bias ,IPAQ ,CH - Child Health ,Surveys and Questionnaires ,Statistics ,Humans ,differential item functioning ,Orthopedics and Sports Medicine ,Dimension (data warehouse) ,Face validity ,Analysis of Variance ,Chi-Square Distribution ,Data collection ,Data Collection ,Comparability ,item response theory ,Middle Aged ,Differential item functioning ,BSS - Behavioural and Societal Sciences ,Europe ,Health ,Scale (social sciences) ,Female ,Psychology ,Social psychology ,Healthy Living ,Human - Abstract
Background:Many questionnaires for measuring physical activity (PA) exist. This complicates the comparison of outcomes.Methods:In 8 European countries, PA was measured in random samples of 600 persons, using the IPAQ as a ‘bridge’ to historical sets of country-specific questions. We assume that a unidimensional scale of PA ability exists on which items and respondents can be placed, irrespective of country, culture, background factors, or measurement instrument. Response Conversion (RC) based on Item Response Theory (IRT) was used to estimate such a common PA scale, to compare PA levels between countries, and to create a conversion key. Comparisons were made with Eurobarometer (IPAQ) data.Results:Appropriateness of IRT was supported by the existence of a strong first dimension established by principal component analysis. The IRT analysis resulted in 1 common PA scale with a reasonable fit and face validity. However, evidence for cultural bias (Differential Item Functioning, DIF) was found in all IPAQ items. This result made actual comparison between countries difficult.Conclusions:Response Conversion can improve comparability in the field of PA. RC needs common items that are culturally unbiased. Wide-scale use of RC awaits measures that are more culturally invariant (such as international accelerometer data).
- Published
- 2012