Validity arguments for patient-reported outcomes: justifying the intended interpretation and use of data.

Kane's five inferences and associated warrants and assumptions were demonstrated in relation to the HLQ. However, the process developed in this study is likely to be suitable for validation planning for other measurement instruments. Systematic and transparent validation planning and the generation (or, as in this study, collation) of relevant validity evidence supports developers and users of PRO instruments to determine the extent to which inferences about data are appropriate, meaningful and useful (i.e., valid) for intended decisions about the health and care of individuals, groups and populations.