Validity parameters for outcome measures
| Construct validity | Disease activity measures should change in the same direction as the patient changes clinically |
| Content validity | All aspects of clinical change should be captured by a set of outcome measures (not necessarily by each one) |
| Face validity | Outcome measures should appear sensible |
| Criterion validity | Ability of outcome measure to predict a long term outcome of importance |
| Discriminant validity | Outcome measure’s responsiveness or sensitivity to change |