prev next front |1 |2 |3 |4 |5 |6 |7 |8 |9 |10 |11 |12 |13 |14 |15 |16 |17 |18 |19 |20 |21 |22 |23 |24 |25 |26 |27 |28 |29 |review
- In a validation study, we compare estimates of physical activity made by a questionnaire with those measured by a more accurate method, ideally a gold standard.

- Epidemiologic studies are most interested in assessing typical or long-term physical activity due to its potential association with disease.

- However, there are no perfect measures of typical or long-term physical activity. All measures have error, although they differ in magnitude and type.

- Given that neither the questionnaire nor the comparison measure will be perfect, the error of both should be as uncorrelated as possible to avoid falsely high estimates of validity.