- In the prior study design example, Pearson correlation coefficients were used to correlate the questionnaire with the comparison method (the average of 4 PALs).

- It is useful to present correlations for overall activity, as well as activity according to intensity and type.

- As noted for reproducibility studies, correlation coefficients ranging from 0.5 to 0.7 are not unusual for physical activity validation studies. Although these values are lower than those observed for laboratory science, these questionnaires have been strong and consistent predictors of disease.