Table 1.

Outcome measures per measurement properties

Measurement property	Measure(s) of effect
Self-reported outcome measurement development	Concept elicitation: sample size (evaluated based on COSMIN guidelines) [20, 22]
	Cognitive interview study: number of patients per item
	Comprehensiveness: number of patients per item
Content validity	Relevance (patients): number of patients per item
	Comprehensiveness (patient): number of patients per item
	Comprehensibility (patient): number of patients per item
	Relevance (professionals): number of professionals per item
Structural validity	Exploratory factor analysis (EFA)
	Confirmatory factor analysis (CFA)
Internal consistency	Continuous scores: Cronbach’s alpha or omega
	Dichotomous scores: Cronbach’s alpha or KR-20
	Item response theory (IRT)-based scores: SE (θ) or reliability coefficient
Reliability	Continuous scores: intraclass correlation coefficient (ICC)
	Dichotomous/nominal/ordinal scores: kappa, weighted kappa (ordinal scores)
Cross-cultural validity	Whether the PROM shows similar structural validity and reliability when validated in another cultural context or translated to another language