Every day I come across posts like this:
"Nearly half of U.S. adults lack the literacy skills needed to manage their health care…” and “90 million Americans cannot read…”
These overstatements underestimate patients and over simplify health literacy. Here’s the history:
The statements are based on a misinterpretation of the findings of the 1992 National Adult Literacy Survey (NALS). Soon after publication of NALS results, authoritative reports stated –incorrectly- "over half the U.S. adult population, 90 million Americans, lack the literacy skills necessary to function in the healthcare system"1,2. Over the next decade, this finding was repeated in the journals of nearly every medical specialty to document the significance and prevalence of low literacy in patient populations 3-7.
These research reports erroneously discussed the NALS literacy levels as standards of literacy and inferred health literacy standards. For example, a 1999 AMA Council on Scientific Affairs report on health literacy states “The 1992 National Adult Literacy Survey (NALS), the most accurate portrait of English language literacy in the United States , found that 40 to 44 million Americans, or approximately one quarter of the US population, are functionally illiterate and another 50 million have marginal literacy skills 8.
Subsequent writings repeated and extended inferences from official reports of NALS results. For example, a 2004 Institute of Medicine (IOM) report9 assigns a reading grade level equivalent (below high school level) to NALS proficiency Levels 1 and 2 despite the expressed intent of NALS designers to move away from reporting adult literacy in this way since the practice is uninformative and often misleading. The IOM report continues the erroneous practice of using NALS proficiency levels as standards of literacy and infers a standard for using the healthcare system referring to “90 million American adults who lack the functional literacy skills in English to use the U.S. health care system” Seven years later, despite retractions published in national newspapers and official reports by the National Academy of Science and testing officials 10, this inaccurate statement continues to be repeated frequently in the literature.
Read critically! Interpret health literacy studies with awareness that national literacy surveys may underestimate adult literacy, and that health literacy studies and cost estimates may be based on unsupported inferences about what constitutes adequate reading ability in a clinical setting.
1.Williams, M.V., Parker, R.M., Baker, D.W., Parikh, N.S., Pitkin, K., Coates, W.C., et al. (1995). Inadequate functional health literacy among patients at two public hospitals. Journal of the American Medical Association, 274,1677-1682.
2. Parker, R.M., Baker, D.W., Williams, M.V., Nurss, J.R. (1995). The Test of Functional Health Literacy in Adults: A new instrument for measuring patients‟ literacy skills. Journal of General Internal Medicine, 10, 537-42.
3. Baker, D.W., Parker, R.M., Williams, M.V., Clark, W.S. & Nurss, J. (1997). The relationship of patient reading ability to self-reported health and use of health services. American Journal of Public Health, 87 (6), 1027-1030.
4. Moon, R.Y., Cheng, T.L., Patel, K.M., Baumhaft, K. & Scheidt, P.C. (1998). Parental literacy level and understanding of medical information. Pediatrics 102, (4). Retrieved on February 9, 2009 from http://pediatrics.aappublications.org/cgi/content/full/102/2/e25#Top.
5. Baker, D.W., Parker, R.M., Williams, M.V. & Clark, W.S. (1998). Health literacy and the risk of hospital admission. Journal of General Internal Medicine, 13, 791-8.
6. Baker, D.W., Williams, M.V., Parker, R.M., Gazmararian, J.A. & Nurss, J. (1999). Development of a brief test to measure functional health literacy. Patient Education and Counseling, 38, 33-42.
7. Schillinger, D., Grumbach, K., Piette, J. (2002). Association of health literacy with diabetes outcomes. Journal of the American Medical Association, 228(4), 475-82.
8. American Medical Association. (1999). Ad Hoc Committee on Health Literacy for the Council on Scientific Affairs. Health literacy: Report of the Council on Scientific Affairs. Journal of the American Medical Association, 281, 552-7.
9.Institute of Medicine. (2004a). Health literacy: A prescription to end confusion. Committee on Health Literacy, Board of Neuroscience and Behavioral Health. Nielsen-Bohlman, A.M. & Kendig, D.A. (Eds.). (2004). Washington, DC: National Academies Press.
10. Kirsch, I., Jungeblut, A., Jenkins, L. & Kolstad, A. (1993) Adult literacy in America: The first look at results of the