- Validity answers the question, “How well does the questionnaire measure what it is designed to measure?”

- Validity implies that a comparison is made with a superior, although typically imperfect, standard.

- A validation study can and should evaluate the questionnaire’s assessment of the type of activity. Examples of different activity types include recreational activity such as exercise, occupational activity, household activity, as well as childcare.

- Validation studies should also assess the questionnaire’s assessment of frequency – how often the activity is performed, its duration – how long it is performed for each bout, as well as its intensity – the effort expended to conduct the activity.