President and Adjunct Professor.
The content validity index: Are you sure you know what's being reported? critique and recommendations
Article first published online: 14 SEP 2006
Copyright © 2006 Wiley Periodicals, Inc.
Research in Nursing & Health
Volume 29, Issue 5, pages 489–497, October 2006
How to Cite
Polit, D. F. and Beck, C. T. (2006), The content validity index: Are you sure you know what's being reported? critique and recommendations. Res. Nurs. Health, 29: 489–497. doi: 10.1002/nur.20147
- Issue published online: 14 SEP 2006
- Article first published online: 14 SEP 2006
- Manuscript Accepted: 16 MAY 2006
- instrument development and validation;
- methodological research;
- scaling; content validity
Scale developers often provide evidence of content validity by computing a content validity index (CVI), using ratings of item relevance by content experts. We analyzed how nurse researchers have defined and calculated the CVI, and found considerable consistency for item-level CVIs (I-CVIs). However, there are two alternative, but unacknowledged, methods of computing the scale-level index (S-CVI). One method requires universal agreement among experts, but a less conservative method averages the item-level CVIs. Using backward inference with a purposive sample of scale development studies, we found that both methods are being used by nurse researchers, although it was not always possible to infer the calculation method. The two approaches can lead to different values, making it risky to draw conclusions about content validity. Scale developers should indicate which method was used to provide readers with interpretable content validity information. © 2006 Wiley Periodicals, Inc. Res Nurs Health 29: 489–497, 2006