The development of more accurate and precise methods of assessing physical activity behavior is an important public health research priority. Objective monitoring devices have advantages but the high cost and burden of data processing make them impractical for large scale applications. Subjective (survey-based) tools are inexpensive and easy to use but these suffer from questionable validity. Objective measures are often used to validate less accurate measures such as subjective instruments but this does not directly improve the accuracy or precision of the self-report instrument. The proposed line of research developed and tested a calibration equation approach that enabled data from a self-report instrument to be linked to, and scaled from, data from an objective monitoring device. This line of research was developed in a series of three studies and culminated with the development and calibration of a new self-report tool: the Youth Activity Profile.

This work provides good evidence that the utility of self-report tools can be improved. Minutes of activity can be directly obtained from these tools if researchers select adequate calibration procedures. To our knowledge the Youth Activity Profile is the first self-report instrument designed to facilitate recall in youth while providing detailed information about activity patterns during important periods of the week (e.g., school time, home, weekend).