Validation of screening questions for limited health literacy in a large VA outpatient population.

OBJECTIVES: Previous studies have shown that a single question may identify individuals with inadequate health literacy. We evaluated and compared the performance of 3 health literacy screening questions for detecting patients with inadequate or marginal health literacy in a large VA population. METHODS: We conducted in-person interviews among a random sample of patients from 4 VA medical centers that included 3 health literacy screening questions and 2 validated health literacy measures. Patients were classified as having inadequate, marginal, or adequate health literacy based on the Short Test of Functional Health Literacy in Adults (S-TOFHLA) and the Rapid Estimate of Adult Literacy in Medicine (REALM). We evaluated the ability of each of 3 questions to detect: 1) inadequate and the combination of "inadequate or marginal" health literacy based on the S-TOFHLA and 2) inadequate and the combination of "inadequate or marginal" health literacy based on the REALM. MEASUREMENTS AND MAIN RESULTS: Of 4,384 patients, 1,796 (41%) completed interviews. The prevalences of inadequate health literacy were 6.8% and 4.2%, based on the S-TOHFLA and REALM, respectively. Comparable prevalences for marginal health literacy were 7.4% and 17%, respectively. For detecting inadequate health literacy, "How confident are you filling out medical forms by yourself?" had the largest area under the Receiver Operating Characteristic Curve (AUROC) of 0.74 (95% CI: 0.69-0.79) and 0.84 (95% CI: 0.79-0.89) based on the S-TOFHLA and REALM, respectively. AUROCs were lower for detecting "inadequate or marginal" health literacy than for detecting inadequate health literacy for each of the 3 questions. CONCLUSION: A single question may be useful for detecting patients with inadequate health literacy in a VA population.

Mixed-mode administration reduced bias and enhanced poststratification adjustments in a health behavior survey.

OBJECTIVE: To assess whether a mixed-mode survey design reduced bias and enhanced methods commonly used to correct for bias (poststratification weighting). STUDY DESIGN AND SETTING: The data for this paper are from a study of 1,900 adult patients enrolled in a randomized controlled trial to promote repeat treatment for relapsed smokers at five Veteran's Affairs Medical Centers. A sequential mixed-mode design was used for data collection whereby the initial attempt was conducted using phone administration, with mail follow-up for nonresponders. Analyses examined demographic, health, and smoking cessation treatment seeking differences between telephone responders, mail responders, and nonresponders and compared the relative effectiveness of global vs. targeted poststratification weighting adjustments for correcting for response bias. RESULTS: The findings suggest (1) that responders to the additional survey mode (mail) did not significantly differ from responders to the first mode (phone) or nonresponders and (2) that poststratification weighting adjustments that take this additional information into account perform better than the standard global adjustments. CONCLUSIONS: A mixed-mode design can improve survey representativeness and enhance the performance of poststratification weighting adjustments.