Accumulation of behavioral validation evidence for physical activity stage of change.

Objective: The purpose of this study was to accumulate behavioral validity evidence for physical activity Stage of Change (SOC).

Design: Nine studies used a common physical activity SOC measure and examined self-report, objective, and performance physical activity indicators to accumulate behavioral validity evidence for SOC. Type of measure, the strength of the expected relationship between the measure and SOC, and the predicted SOC differences were examined. Validity evidence for the SOC was also examined by population and sampling method.

Main outcome measures: Validity evidence for physical activity SOC was classified with respect to the type of measurement instrument and the hypothesized magnitude of the relationship between the measure and the SOC.

Results: Physical activity SOC was found to be behaviorally valid as evidenced by self-reported physical activity, self-reported exercise, self-reported sedentary behaviors, pedometers, and physical functioning. Physical activity SOC does not appear to be related to physical fitness or weight indicators.

Conclusions: This study highlights a successful multi-site collaboration. Physical activity data from nine large-scale, health trials was combined and accumulated behavioral validation evidence for the physical activity SOC.