- In order to assess reproducibility, questionnaires are administered twice to a group of individuals at 2 points in time. The goal of a reproducibility study is to assess variation in questionnaire performance from one administration to the next.

- Short intervals (i.e., days or weeks) between questionnaire administrations may lead to subjects simply remembering their responses to the first administration and therefore artificially increase observed reproducibility.

- Alternatively, long intervals of time between questionnaire administrations (i.e., one year) may encompass true changes in physical activity and lead to reduced reproducibility.

- One approach to address these problems is to administer the questionnaire over both short as well as long intervals of time to provide an estimate of both the lower as well as upper level of reproducibility.