Test-retest reliability of a questionnaire on physical activity and its correlates among women from diverse racial and ethnic groups

Background: A better understanding of physical activity and its correlates is needed, especially among diverse populations of women. The objective of this study was to examine the test-retest reliability of a survey designed to measure physical activity and its correlates among women from diverse racial and ethnic groups. Methods: Test and retest surveys were conducted in person or over the telephone with 344 white, Latina, African-American, and Native American women aged 20 to 50 years living in rural and urban areas of the United States. Reliability of self-reported physical activity and its correlates were determined using intraclass correlation coefficients (ICC) overall and separately by site and race/ethnicity. Results: Of the women responding, 45% of the participants met recommendations for physical activity, 40% were insufficiently active, and 15% were inactive. Reliability for the physical activity measure was 0.69 (95% confidence interval [CI], 0.62-0.74), with an ICC of 0.30 to 0.95 across sites. Overall, the seven items on the physical environment had substantial reliability (ICC=0.64-0.91). The sense of community scale (0.79; 95% CI, 0.74-0.83), social issues (0.68; 95% CI, 0.61-0.74), social roles (0.64; 95% CI, 0.56-0.71), and self-efficacy for exercise (0.72; 95% CI, 0.66-0.77) all had acceptable reliability overall and across most sites. Conclusions: This study provides psychometric evidence that the questionnaire on physical activity and its correlates is reliable among diverse women aged 20 to 50 years from various racial and ethnic groups. These results suggest that test-retest reliability is not an obstacle to comparison of associations between physical activity and several hypothesized correlates of activity.