Response error in reporting dental coverage by older Americans in the health and retirement study.

Abstract The aim of this research was to analyze the inconsistency in responses to survey questions within the Health and Retirement Study (HRS) regarding insurance coverage of dental services. Self-reports of dental coverage in the dental services section were compared with those in the insurance section of the 2002 HRS to identify inconsistent responses. Logistic regression identified characteristics of persons reporting discrepancies and assessed the effect of measurement error on dental coverage coefficient estimates in dental utilization models. In 18% of cases, data reported in the insurance section contradicted data reported in the dental use section of the HRS by those who said insurance at least partially covered (or would have covered) their (hypothetical) dental use. Additional findings included distinct characteristics of persons with potential reporting errors and a downward bias to the regression coefficient for coverage in a dental use model without controls for inconsistent self-reports of coverage. This study offers evidence for the need to validate self-reports of dental insurance coverage among a survey population of older Americans to obtain more accurate estimates of coverage and its impact on dental utilization. Keywords dental insurance, dental coverage, measurement error, dental use, consistent response Introduction Response variance or unreliability is introduced in surveys when sampled individuals provide different answers to the same question asked more than once in the survey. Response variance is only one example of measurement errors in surveys. (1) The presence of measurement error from inconsistent or unreliable reporting of the explanatory variables in a regression model poses estimation problems that may cause potentially downward biased, inconsistent estimates of the regression coefficients. (2,3) Previous studies have addressed disagreements between survey measurements of public and private health insurance coverage from alternate sources for nonelderly populations. Black et al estimated a 34% downward bias in a wage growth model for the health insurance coefficient from using employee reports of group health insurance coverage instead of the 79% of employee responses that agreed with the employer verification of coverage status. (4) Hill used up to four sources of data including insurance cards, policy booklets, medical providers, and employers and insurance companies, to verify self-reports of health insurance coverage status for 97% of household members in the 1996 Medical Expenditure Panel Survey (MEPS). (5) Call et al estimated from the 2004 Medicaid Undercounts Experiments (MUE) data that between 13% and 20% of surveyed known Medicaid beneficiaries across three states reported no Medicaid coverage at all while 3% to 13% of them in these states reported no coverage from any source. (6) Cafferata verified 70.9% of self-reports of dental service coverage by elderly household members 65 and older against policy documentation collected from employers and insurance providers in the 1977 National Medical Care Expenditure Survey (NMCES). Of the 8.8% self-reporting dental coverage in the household survey, 40% lacked validated coverage. Correct household survey responses were (1) correlated positively with household income and negatively with a person's age, and (2) were more prevalent among whites than non-whites and among those with Medicare and private insurance than other medical insurance coverage. (7) A longitudinal survey of older Americans over 50 years of age was used in our study to identify response inconsistency to survey questions regarding insurance coverage of dental services. In each of four recent waves of the survey administered at 2-year intervals between 2002 and 2008, individuals were asked about dental coverage associated with their use of dental services. Those who did not use dental services were queried as to whether services would have been covered by insurance. …