Using predicted Spanish preference to target bilingual mailings in a mail survey with telephone follow-up.

Objective Spanish-preferring Medicare beneficiaries are underrepresented in national patient experience surveys. We test a method for improving their representation via higher response rates. Data Sources/Study Setting 2009-2010 Medicare CAHPS surveys; Medicare population. Study Design We used surname and address to predict Spanish-language preference for a national sample of 177 139 beneficiaries. We randomized half of the 10 000 non-Puerto Rico beneficiaries with the highest predicted probabilities of Spanish preference (>10 percent) to bilingual mailings (intervention) and half to standard English-only mailings (control). Data Collection Medicare CAHPS Survey data were collected through mail surveys with telephone follow-up of nonrespondents. Principal Findings Mail response rate was higher for intervention (28.7 percent) than control (23.9 percent) (P < 0.0001); phone response rates among mail nonrespondents were similar in intervention and control arms (15.8 percent vs 15.7 percent, P = 0.90). Targeted bilingual mailings induced 6.5 percent of those who would not have responded to respond by mail and 54.0 percent of those who would have responded in English to respond in Spanish. Beneficiaries with greater Spanish probabilities showed greater increases in response rates, a higher proportion of responses in Spanish, and lower control response rates among. Conclusions Targeted bilingual mailing of mixed-mode surveys using commonly available surname and address information can efficiently increase representation of this underrepresented group.