- 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.