Table 2.

Quality criteria for the key measurement properties used in evaluating patient reported outcomes instruments.

Measurement Property	Quality Criteria – Positive Rating
Content Validity	A clear description is provided of the measurement aim, the target population, the concepts that are being measured, and the item selection AND target population and investigators and/or experts were involved in item selection
Internal Consistency	Factor analyses performed on adequate sample size (7 × #items and ≥ 100) AND Cronbach’s alpha(s) calculated per dimension AND Cronbach’s alpha(s) between 0.70 and 0.95
Criterion Validity	Convincing argument that gold standard is “gold” AND correlation with gold standard ≥ 0.70
Construct Validity	Specific hypotheses were formulated AND at least 75% of the results are in accordance with these hypotheses
Reliability	Intraclass correlation coefficient (for continuous measures) or weighted Kappa (for ordinal measures) ≥0.70
Responsiveness	SDC OR SDC < MCID OR MCID outside the limits of agreement OR Guyatt’s responsiveness ratio > 1.96 OR area under the receiver operating curve ≥ 0.70
Floor and Ceiling Effects	≤15% of the respondents achieved the highest or lowest possible scores
Interpretability	Mean and standard deviation scores presented for at least four relevant subgroups of patients AND MCID defined

SDC = Smallest Detectable Change; MCID = Minimal Clinically Important Difference. Adapted from Terwee, C. B., Bot, S. D., de Boer, M. R., et al. Quality criteria were proposed for measurement properties of health status questionnaires. J Clin Epidemiol 60: 34–42, 2007. With Permission