This manuscript describes the development and validation of measures assessing patient knowledge about the risks and benefits of prostate cancer (CaP) screening. The measures described include a 10-item knowledge index and four single-item measures, used in previous studies, that assess knowledge of: CaP natural history and treatment efficacy, expert disagreement over the value of CaP screening, and the accuracy of the prostate specific antigen (PSA) test for CaP. We assessed the validity and reliability of these measures on a sample of 1152 male veteran patients age 50 and older. All knowledge index items had acceptable levels of discrimination, difficulty, and reliability. The index demonstrated strong evidence for construct and criterion validity. Much weaker validity evidence was found for the four single-item knowledge questions. The 10-item index developed in this study provides a valid and reliable tool for assessing patient knowledge of the risks and benefits of CaP screening.
Bibliographical noteFunding Information:
Funded by VA Health Services Research and Development Service grant #IIR 99-277-1 to the Center for Chronic Disease Outcomes Research, Veterans Affairs Medical Center, Minneapolis, MN. The authors thank Drs. Ann Barry Flood, Robert Volk, and Marilyn Schapira for contributing versions of their knowledge instruments for use in this study. The views expressed in this article are those of the authors and do not necessarily represent the views of the US Department of Veterans Affairs.
- Decision making
- Patient education
- Prostate specific antigen
- Prostatic neoplasms
- Risk assessment