Cross-cultural validation of the SQUASH

Self-report questionnaires provide crucial information for the evaluation and development of health promotion interventions. In the Netherlands, the SQUASH (short questionnaire to assess health enhancing physical activity) is the standard instrument to assess the physical activity level. It is widely used by several universities, all Municipal Health Services and Statistics Netherlands. The SQUASH has been validated, but among the ethnic Dutch population only. However, ethnic minorities are often the target of health promotion interventions as these groups have an even higher prevalence of unhealthy lifestyles than the ethnic Dutch. Hence, it is not known whether the SQUASH provides reliable information about the physical activity level in ethnic minorities. The aim of our study is to cross-culturally validate the SQUASH among three main ethnic minority groups in the Netherlands. With this study we aim to provide a tool which validly assesses the effectiveness of health promotion interventions on a significant risk factor (physical activity) in ethnic minorities. Furthermore, we also aim to give insight in the construct and content validity as well as insight in the occurrence of different kinds of bias (construct, method and item bias) per ethnic minority group. This information is relevant for the development of questionnaires on other lifestyle factors (such as smoking and dietary habits) as well. The study will be set up as a prospective validation study. In total 500 participants will be recruited. They will constitute five groups of 100 persons (50 males and 50 females) from different ethnic background, knowingly: ethnic Dutch, Turkish, Moroccan, Surinamese Hindustani and Surinamese Creole. All participants will complete the SQUASH twice, once at baseline and the second time a month later. The SQUASH will be extended with a physical inactivity section to provide physical inactivity patterns of the diverse populations. Also the shortened version of the Marlowe-Crowne scale will be assessed at baseline to explore the occurrence of social desirability in the different ethnic minority groups. At the second visit all subjects will receive a combined accelerometer and heart rate monitor device (Actiheart) that will be worn for a week. Furthermore, to calibrate the Actiheart device, a sub maximal exercise test will be conducted at baseline. To obtain insight in content validity, the occurrence of bias and encountered difficulties of the questionnaire a cognitive interview will be carried out in a subset (15 persons per group). When necessary the SQUASH will be revised on the basis of the cognitive interview. This revised version will again be validated among a randomly chosen group of 20 new participants (5 Turks, 5 Moroccan, 5 Surinamese Hindustani, 5 Surinamese Creole). The same protocol as described above will be followed, with the exception that in all new participants a cognitive interview is conducted. The results of this trial will increase our insight into the validity and reliability of the SQUASH. The SQUASH has already proven its utility in the Dutch society. Hence the results of our study can immediately be implemented into practice, but perhaps just as important, our results also shed light on data about health-enhancing physical activity in ethnic minorities that was obtained in the past years. In other words, our study is relevant for the future, the present as well as the past.