Published Jul 2011
Patrick DL, Burke LB, Gwaltney CJ, et al. Content validity - establishing and reporting the evidence in newly-developed patient-reported outcomes (PRO) Instruments for medical product evaluation: ISPOR PRO Good Research Practices Task Force Report: part 2 – assessing respondent understanding. Value Health. 2011;14(8):978-988.
The importance of content validity in developing patient reported outcomes
(PRO) instruments is stressed by both the US Food and Drug Administration
and the European Medicines Agency. Content validity is the extent to which
an instrument measures the important aspects of concepts developers or
users purport it to assess. A PRO instrument measures the concepts most
relevant and important to a patient’s condition and its treatment. For PRO
instruments, items and domains as reflected in the scores of an instrument
should be important to the target population and comprehensive with respect
to patient concerns.
Documentation of target population input in item generation, as well as evaluation of patient understanding through cognitive interviewing, can provide the evidence for content validity. Part 1 of this task force report covers elicitation of key concepts using qualitative focus groups and/or interviews to inform content and structure of a new PRO instrument. Building on qualitative interviews and focus groups used to elicit concepts, cognitive interviews help developers craft items that can be understood by respondents in the target population and can ultimately confirm that the final instrument is appropriate, comprehensive, and understandable in the target population.
Part 2 details: 1) the methods for conducting cognitive interviews that address patient understanding of items, instructions, and response options; and 2) the methods for tracking item development through the various stages of research and preparing this tracking for submission to regulatory agencies. The task force report’s two parts are meant to be read together. They are intended to offer suggestions for good practice in planning, executing, and documenting qualitative studies that are used to support the content validity of PRO instruments to be used in medical product evaluation.
Keywords: content validity, instrument development, patient-reported outcomes, qualitative research, regulatory.
Copyright © 2011, International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc.