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. 2018 May;27(5):1159-1170.
doi: 10.1007/s11136-018-1829-0. Epub 2018 Mar 17.

COSMIN methodology for evaluating the content validity of patient-reported outcome measures: a Delphi study

C B Terwee  1 , C A C Prinsen  2 , A Chiarotto  2 , M J Westerman  3 , D L Patrick  4 , J Alonso  5   6 , L M Bouter  2   7 , H C W de Vet  2 , L B Mokkink  2
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COSMIN methodology for evaluating the content validity of patient-reported outcome measures: a Delphi study

C B Terwee et al. Qual Life Res. 2018 May.

Abstract

Background: Content validity is the most important measurement property of a patient-reported outcome measure (PROM) and the most challenging to assess. Our aims were to: (1) develop standards for evaluating the quality of PROM development; (2) update the original COSMIN standards for assessing the quality of content validity studies of PROMs; (3) develop criteria for what constitutes good content validity of PROMs, and (4) develop a rating system for summarizing the evidence on a PROM's content validity and grading the quality of the evidence in systematic reviews of PROMs.

Methods: An online 4-round Delphi study was performed among 159 experts from 21 countries. Panelists rated the degree to which they (dis)agreed to proposed standards, criteria, and rating issues on 5-point rating scales ('strongly disagree' to 'strongly agree'), and provided arguments for their ratings.

Results: Discussion focused on sample size requirements, recording and field notes, transcribing cognitive interviews, and data coding. After four rounds, the required 67% consensus was reached on all standards, criteria, and rating issues. After pilot-testing, the steering committee made some final changes. Ten criteria for good content validity were defined regarding item relevance, appropriateness of response options and recall period, comprehensiveness, and comprehensibility of the PROM.

Discussion: The consensus-based COSMIN methodology for content validity is more detailed, standardized, and transparent than earlier published guidelines, including the previous COSMIN standards. This methodology can contribute to the selection and use of high-quality PROMs in research and clinical practice.

Keywords: COSMIN; Content validity; Patient outcome assessment; Patient-reported outcome; Systematic review; Validation studies.

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Conflict of interest statement

Conflict of interest

All authors declare that they have no conflict of interest.

Ethical approval

As this study did not involve experiments with patients or study subjects, it was exempt from ethical approval according to the Dutch Medical Research in Human Subjects Act (WMO).

Human and animal rights

All procedures performed in this study involving human participants were in accordance with the ethical standards of the institutional and national research committees and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. This article does not contain any studies with animals performed by any of the authors.

Informed consent

According to the Dutch Medical Research in Human Subjects Act (WMO), obtaining informed consent was not necessary.

Figures

Fig. 1
Fig. 1
Design of the Delphi study
Fig. 2
Fig. 2
Supplementary flow chart for grading the quality of evidence
See this image and copyright information in PMC

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