Table 1.

Summary of FDA Recommendations for the Psychometric Properties of a Patient-Reported Outcomes Instrument

Property	FDA PRO Guidance Recommendations
Conceptual framework	Should be confirmed by using empirical evidence during instrument development
	Explicit statement of relationship among instruments’ concepts, domains, and items
	Response options should be clear and appropriate.
Reliability	Instrument should demonstrate test-retest reliability.
	Instrument should demonstrate internal consistency.
Content validity	Must encompass most important and comprehensive outcomes for patients
	Patient input should be sought for item generation.
	Patient input should be sought until point of saturation.
Construct validity	Obtained results should be consistent with preexisting hypotheses.
	Instrument should have the ability to differentiate between clinically distinct groups.
Clinical relevance of score changes	Instrument should be equally sensitive to gains and losses in health status.
	Instrument should be sensitive to change at all points for the clinical population.

Abbreviations: FDA, Food and Drug Administration; PRO, patient-reported outcome.