Objectives: This paper compares estimates of poor health literacy using two widely used assessment tools and assesses the effect of non-response on these estimates. Study Design and Setting: A total of 4,868 veterans receiving care at four VA medical facilities between 2004 and 2005 were stratified by age and facility and randomly selected for recruitment. Interviewers collected demographic information and conducted assessments of health literacy (both REALM and S-TOFHLA) from 1,796 participants. Prevalence estimates for each assessment were computed. Non-respondents received a brief proxy questionnaire with demographic and self-report literacy questions to assess non-response bias. Available administrative data for non-participants were also used to assess non-response bias. Results: Among the 1,796 patients assessed using the S-TOFHLA, 8% had inadequate and 7% had marginal skills. For the REALM, 4% were categorized with 6th grade skills and 17% with 7-8th grade skills. Adjusting for non-response bias increased the S-TOFHLA prevalence estimates for inadequate and marginal skills to 9.3% and 11.8%, respectively, and the REALM estimates for∈6th and 7-8th grade skills to 5.4% and 33.8%, respectively. Conclusions: Estimates of poor health literacy varied by the assessment used, especially after adjusting for non-response bias. Researchers and clinicians should consider the possible limitations of each assessment when considering the most suitable tool for their purposes.
Bibliographical noteFunding Information:
Acknowledgements: This research was supported by the Department of Veterans Affairs, including a grant from VA Health Services Research and Development Service (CRI-03-151-1). Dr. Griffin also received support as a VA Merit Review Entry Program (MREP) awardee. Dr. Gralnek was supported by a VA HSR&D Advanced Research Career Development Award and IIS 01-191-1. The views expressed in this article are those of the author(s) and do not necessarily represent the views of the Department of Veterans Affairs or the United States Government. Part of this work was presented at the 24th Annual VA Health Services Research Meeting, Crystal City, VA, February 17, 2006. The authors wish to thank all the veteran participants for their time and the study interviewers for their commitment to this project.
Copyright 2011 Elsevier B.V., All rights reserved.
- health literacy
- non-response bias