Table 1.

Definitions of measurement properties [33]

Measurement property	Definition
Content development	The degree to which the content of a measurement instrument is an adequate reflection of the construct to be measured
Internal consistency	The degree to which different items of a (sub)scale correlate and measure the same construct (interrelatedness)
Reliability	The extent to which scores for persons who have not changed are the same for repeated measurement under several conditions
Structural validity	The degree to which the scores of an instrument are an adequate reflection of the dimensionality of the construct to be measured
Criterion validity	The degree to which the scores of an instrument are an adequate reflection of a ‘golden standard’
Hypothesis testing for construct validity	The degree to which the scores of the instrument are consistent with the hypotheses based on the assumption that the instrument measures the construct to be measured
Measurement error	The systematic and random error of a patient’s score that is not attributed to true changes in the construct to be measured
Responsiveness	The ability of an instrument to detect change over time in the construct to be measured