Impact of nonresponse on Medicare Current Beneficiary Survey estimates.

The Medicare Current Beneficiary Survey (MCBS) has been used by policymakers and research analysts to provide information on a wide array of topics about the Medicare Program. Nonresponse bias is potentially one of the most important threats to the validity of the estimates from the MCBS. In this article we present results of our methodological study that analyzes the impact of nonresponse on MCBS estimates, including initial round unit nonresponse, panel attrition, and item nonresponse. Our findings indicate that for most of the measures studied, the bias caused by differences between nonrespondents and respondents in the MCBS was substantially reduced or eliminated by the nonresponse procedures currently employed.

Epidemiology of undiagnosed trichomoniasis in a probability sample of urban young adults.

T. vaginalis infection (trichomoniasis) is the most common curable sexually transmitted infection (STI) in the U.S. It is associated with increased HIV risk and adverse pregnancy outcomes. Trichomoniasis surveillance data do not exist for either national or local populations. The Monitoring STIs Survey Program (MSSP) collected survey data and specimens which were tested using nucleic acid amplification tests to monitor trichomoniasis and other STIs in 2006-09 among a probability sample of young adults (N = 2,936) in Baltimore, Maryland--an urban area with high rates of reported STIs. The estimated prevalence of trichomoniasis was 7.5% (95% CI 6.3, 9.1) in the overall population and 16.1% (95% CI 13.0, 19.8) among Black women. The overwhelming majority of infected men (98.5%) and women (73.3%) were asymptomatic. Infections were more common in both women (OR = 3.6, 95% CI 1.6, 8.2) and men (OR = 9.0, 95% CI 1.8, 44.3) with concurrent chlamydial infection. Trichomoniasis did not vary significantly by age for either men or women. Women with two or more partners in the past year and women with a history of personal or partner incarceration were more likely to have an infection. Overall, these results suggest that routine T vaginalis screening in populations at elevated risk of infection should be considered.

The National Survey on Drug Use and Health Mental Health Surveillance Study: calibration analysis.

The Mental Health Surveillance Study (MHSS) is an ongoing initiative by the Substance Abuse and Mental Health Services Administration to develop and implement methods for measuring the prevalence of serious mental illness (SMI) among adults in the USA. The 2008 MHSS used data from clinical interviews administered to a sub-sample of respondents to calibrate mental health screening scale data from the National Survey on Drug Use and Health (NSDUH) for estimating the prevalence of SMI in the full NSDUH sample. The mental health scales included the K6 screening scale of psychological distress (administered to all respondents) along with two measures of functional impairment (each administered to a random half-sample of respondents): the World Health Organization Disability Assessment Schedule (WHODAS) and the Sheehan Disability Scale (SDS). The Structured Clinical Interview for DSM-IV (SCID) was administered to a sub-sample of 1506 adult NSDUH respondents within 4 weeks of completing the NSDUH interview. Results indicate that while SMI prediction accuracy of the K6 is improved by adding either the WHODAS or the SDS to the prediction equation, the models with the WHODAS are more robust. The results of the calibration study and methods used to derive prevalence estimates of SMI are presented.

Improving epidemiological surveys of sexual behaviour conducted by telephone.

BACKGROUND: This study assesses the impact of Telephone Audio Computer-Assisted Self-Interviewing (T-ACASI) on the reporting of sensitive (mainly heterosexual) behaviours. METHODS: A randomized experiment was embedded in a telephone survey that drew probability samples of the populations of the USA (N = 1543) and Baltimore city (N = 744). Respondents were randomly assigned to have questions asked either by a T-ACASI computer or by a human telephone interviewer. RESULTS: Compared with interviewer-administered telephone surveys, T-ACASI obtained more frequent reporting of a range of mainly heterosexual behaviours that were presumed to be sensitive, including recency of anal sex [adjusted odds ratio (A-OR) = 2.00, P < 0.001), sex during menstrual period (A-OR = 1.49, P < 0.001), giving oral sex (A-OR = 1.40, P = 0.001) and receiving oral sex (A-OR = 1.36, P = 0.002), and sexual difficulties for the respondent (A-OR = 1.45, P = 0.034) and their main sex partner (A-OR = 1.48, P = 0.0). T-ACASI also obtained less frequent reporting that respondent had a 'main sex partner' (A-OR = 0.56, P = 0.011) and discussed contraception prior to first sex with that sex partner (A-OR = 0.82, P = 0.094). For both males and females, T-ACASI obtained more frequent reports of first vaginal sex occurring at early ages (before ages 12 through 15). 'For males only', T-ACASI also elicited more frequent reports that first vaginal sex had 'not' occurred at later ages (i.e. by ages 20 through 24). CONCLUSION: T-ACASI increases the likelihood that survey respondents will report sensitive heterosexual behaviours.

Impact of T-ACASI on Survey Measurements of Subjective Phenomena.

Numerous studies have shown that audio-computer-assisted self-interviewing (audio-CASI) and telephone audio-CASI (T-ACASI) technologies yield increased reporting of sensitive and stigmatized objective phenomena such as sexual and drug use behaviors. Little attention has been given, however, to the impact of these technologies on the measurement of subjective phenomena (attitudes, opinions, feelings, etc.). This article reports results for the seven subjective measurements included in the National STD and Behavior Measurement Experiment (NSBME). NSBME drew probability samples of USA and Baltimore adults (Ns = 1,543 and 744, respectively) and randomized these respondents to be interviewed by T-ACASI or telephone interviewer-administered questioning (T-IAQ). Response distributions for all subjective measurements obtained by T-ACASI diverge from those obtained by human telephone interviewers. For six of our seven ordinal-scaled measurements, this divergence involved shifting responses directionally along the ordinal scale, as opposed to a nondirectional redistribution among response categories. When interviewed by T-ACASI, respondents were more supportive of traditional gender roles and corporal punishment, less supportive of integrated neighborhoods and same-gender sex, and more likely to agree that occasional marijuana use is harmless and to describe themselves as attractive. The majority of these results suggest that telephone survey respondents may provide more "tolerant" and "socially liberal" responses to human interviewers than to a T-ACASI computer. Similarly, although the evidence is not entirely consistent, the impact of T-ACASI appears to increase with the social vulnerability of the population surveyed.

T-ACASI reduces bias in STD measurements: the National STD and Behavior Measurement Experiment.

BACKGROUND: Although telephone surveys provide an economical method for assessing patterns of diagnosed sexually transmitted diseases (STDs) and STD-related behaviors in populations, the requirement that respondents report such information to human telephone interviewers introduces an opportunity for substantial reporting bias. Telephone computer-assisted self-interviewing (T-ACASI) surveys substitute a computer for human interviewers when asking sensitive questions. METHODS: A randomized experiment was embedded in a telephone survey that drew probability samples of the populations of the United States (N = 1543) and Baltimore city (N = 744). Respondents were randomly assigned to have sensitive questions asked either by a T-ACASI computer or by a human telephone interviewer. RESULTS: Respondents interviewed by a T-ACASI computer were more likely to report STD symptoms [dysuria, genital sores, genital discharge, and genital warts; adjusted odds ratios (ORs) = 1.5-2.8] and a diagnosis of gonococcal or chlamydial infection during the past year (adjusted ORs = 3.6 and 6.1). T-ACASI respondents with a main sex partner in the past year were more likely to report that their partner has had an STD (adjusted OR = 2.4). For some measurements, the impact of T-ACASI was strongest among younger and less-educated respondents. When sampling weights were applied to project National STD and Behavior Measurement Experiment results to the populations of the United States and Baltimore, we found that reliance on data obtained by human interviewers would underestimate the annual incidence of chlamydial and gonococcal infections in these populations by factors of 2.4 to 9.7. CONCLUSIONS: Compared with human telephone interviewers, T-ACASI surveys obtain increased reporting of STD symptoms, infections, and STD-related behaviors.

SAME-GENDER SEX AMONG U.S. ADULTS: TRENDS ACROSS THE TWENTIETH CENTURY AND DURING THE 1990s.

Trends in reporting of same-gender sex are assessed using data from the 1988-2002 General Social Surveys (Ns = 9,487 males and 12,336 females). Analyses indicate that the reported prevalence of female-female sexual contact increased substantially and monotonically across twentieth-century birth cohorts, rising from 1.6 percent (Standard error [SE] = 0.60) for the cohort of U.S. women born prior to 1920 to 6.9 percent (SE = 0.81) for women born in 1970 and afterward. Increases in the reported prevalence of female-female contacts also occurred within the 1990s. These trends persist when statistical controls are introduced for changes in attitudes toward same-gender sexual behavior. No parallel trend is observed in the reporting of male-male sexual contacts during adulthood, although the proportion of U.S. men reporting such contacts in the past year and in the past five years increased during the 1990s.

Untreated gonococcal and chlamydial infection in a probability sample of adults.

CONTEXT: The prevalence and distribution of gonococcal and chlamydial infections in the general population are poorly understood. Development of nucleic acid amplification tests, such as the ligase chain reaction assay, provides new opportunities to estimate the prevalence of untreated infections in the population. OBJECTIVE: To estimate the overall prevalence of untreated gonococcal and chlamydial infections and to describe patterns of infection within specific demographic subgroups of the young adult population in Baltimore, Md. DESIGN AND SETTING: Cross-sectional behavioral survey based on a probability sample of Baltimore households with collection of urine specimens between January 1997 and September 1998. PARTICIPANTS: A total of 728 adults aged 18 to 35 years completed the interview portion of the study, and 579 of these respondents also provided a urine specimen adequate for testing. MAIN OUTCOME MEASURE: Prevalence of untreated infection, as measured by the percentage of specimens testing positive for gonococcal and chlamydial infection by ligase chain reaction, weighted to reflect variations in probabilities of sample selection from the population. Alternate estimates of the prevalence of recent treated infection were derived from clinically diagnosed cases reported to the Baltimore City Health Department and by diagnoses reported by participants in the survey. RESULTS: An estimated 5.3% (SE, 1.4%) of the population aged 18 to 35 years has an untreated gonococcal infection, and 3.0% (SE, 0.8%) is estimated to have an untreated chlamydial infection. While 7.9% (SE, 1.6%) of the population is estimated to have either an untreated gonococcal or chlamydial infection, estimated prevalence is substantially higher among black women (15.0%; SE, 3.7%). Few participants with untreated infections reported dysuria or discharge during the 6 months preceding testing. The estimated number of untreated gonococcal infections in the population (9241; SE, 2441) substantially exceeds both the number of such infections diagnosed among Baltimore adults aged 18 to 35 years and reported to the Baltimore City Health Department during 1998 (4566), and the estimated number of diagnoses derived using participants' reports for the 12 months prior to the survey (4708 [SE, 1918] to 5231 [SE, 2092]). The estimated number of untreated chlamydial infections (5231; SE, 1395) is also greater than the number of cases reported to the health department in 1998 (3664) but is slightly less than the estimated number of diagnoses derived using participants' reports of chlamydial infections diagnosed during the 12 months prior to the survey (5580 [SE, 1918] to 6975 [SE, 2441]). CONCLUSION: In 1997-1998, the estimated number of undiagnosed gonococcal and chlamydial infections prevalent in the population of Baltimore adults aged 18 to 35 years approached or exceeded the number of infections that were diagnosed and treated annually.