Differences in mail and telephone responses to self-rated health: use of multiple imputation in correcting for response bias

Objectives: To estimate differences in self-rated health by mode of administration and to assess the value of multiple imputation to make self-rated health comparable for telephone and mail. Methods: In 1996, Survey 1 of the Australian Longitudinal Study on Women's Health was answered by mail. In 1998, 706 and 11,595 mid-age women answered Survey 2 by telephone and mail respectively. Self-rated health was measured by the physical and mental health scores of the SF-36. Mean change in SF-36 scores between Surveys 1 and 2 were compared for telephone and mail respondents to Survey 2, before and after adjustment for socio-demographic and health characteristics. Missing values and SF-36 scores for telephone respondents at Survey 2 were imputed from SF-36 mail responses and telephone and mail responses to socio-demographic and health questions. Results: At Survey 2, self-rated health improved for telephone respondents but not mail respondents. After adjustment, mean changes in physical health and mental health scores remained higher (0.4 and 1.6 respectively) for telephone respondents compared with mail respondents (-1.2 and 0.1 respectively). Multiple imputation yielded adjusted changes in SF-36 scores that were similar for telephone and mail respondents. Conclusions and Implications: The effect of mode of administration on the change in mental health is important given that a difference of two points in SF-36 scores is accepted as clinically meaningful. Health evaluators should be aware of and adjust for the effects of mode of administration on self-rated health. Multiple imputation is one method that may be used to adjust SF-36 scores for mode of administration bias.

Effect on trend estimates of the difference between survey respondents and non-respondents: Results from 27 populations in the WHO MONIICA Project

Introduction: In the World Health Organization (WHO) MONICA (multinational MONItoring of trends and determinants in CArdiovascular disease) Project considerable effort was made to obtain basic data on non-respondents to community based surveys of cardiovascular risk factors. The first purpose of this paper is to examine differences in socio-economic and health profiles among respondents and non-respondents. The second purpose is to investigate the effect of non-response on estimates of trends. Methods:Socio-economic and health profile between respondents and non-respondents in the WHO MONICA Project final survey were compared. The potential effect of non-response on the trend estimates between the initial survey and final survey approximately ten years later was investigated using both MONICA data and hypothetical data. Results: In most of the populations, non-respondents were more likely to be single, less well educated, and had poorer lifestyles and health profiles than respondents. As an example of the consequences, temporal trends in prevalence of daily smokers are shown to be overestimated in most populations if they were based only on data from respondents. Conclusions: The socio-economic and health profiles of respondents and non-respondents differed fairly consistently across 27 populations. Hence, the estimators of population trends based on respondent data are likely to be biased. Declining response rates therefore pose a threat to the accuracy of estimates of risk factor trends in many countries.

Lifetime prevalence estimates of major depression: An indirect estimation method and a quantification of recall bias

The measurement of lifetime prevalence of depression in cross-sectional surveys is biased by recall problems. We estimated it indirectly for two countries using modelling, and quantified the underestimation in the empirical estimate for one. A microsimulation model was used to generate population-based epidemiological measures of depression. We fitted the model to 1-and 12-month prevalence data from the Netherlands Mental Health Survey and Incidence Study (NEMESIS) and the Australian Adult Mental Health and Wellbeing Survey. The lowest proportion of cases ever having an episode in their life is 30% of men and 40% of women, for both countries. This corresponds to a lifetime prevalence of 20 and 30%, respectively, in a cross-sectional setting (aged 15-65). The NEMESIS data were 38% lower than these estimates. We conclude that modelling enabled us to estimate lifetime prevalence of depression indirectly. This method is useful in the absence of direct measurement, but also showed that direct estimates are underestimated by recall bias and by the cross-sectional setting.

Keeping it in-house: How audience affects responses to group criticism

It is often assumed that group-directed criticism is best kept 'in-house', but the effects of audience on responses to criticism have not been directly examined. Consistent with predictions, ingroup members who criticized the group to an outgroup audience were seen to be making a less appropriate choice of audience (Experiments 2 and 3), aroused more negative feelings (Experiment 1), were downgraded more strongly on personality traits (Experiment 2), and were seen to be doing more damage to the group (Experiment 2) than were ingroup members who kept their criticisms in-house. Experiment 3 showed that, whereas moderate identifiers agreed with the comments less and showed weaker friendly intentions toward the critic when an outgroup audience as compared to an ingroup audience was chosen, high identifiers agreed with the criticisms just as strongly-and showed more friendly intentions toward the critic-when they were made to an outgroup as compared to an ingroup audience. Results are discussed in light of the broader literature on identity threat. Copyright © 2005 John Wiley & Sons, Ltd.

Perceptions of the intergroup structure and anti-Asian prejudice among white Australians

Subjective intergroup beliefs and authoritarianism were assessed in a field study (N=255) of White Australians' anti-Asian stereotyping and prejudice. A social identity analysis of intergroup prejudice was adopted, such that perceptions of the intergroup structure (instability, permeability, legitimacy and higher ingroup status) were proposed as predictors of higher prejudice (blatant and covert) and less favorable stereotyping. Consistent with the social identity approach, both independent and interacting roles for sociostructural predictors of Anti-Asian bias were observed, even after demographic and personality variables were controlled. For example, perceived legitimacy was associated with higher prejudice when White Australians' status position relative to Asian Australians was valued. Moreover, when participants evaluated Whites' position as unstable and high status or legitimate, perceptions of permeable intergroup boundaries were associated with anti-Asian bias. The present findings demonstrate status protection responses in advantaged group members in a field setting, lending weight to the contention that perceptions of sociostructural threat interact to predict outgroup derogation. Implications for theories of intergroup relations are discussed.

Attentional bias to pictures of fear-relevant animals in a dot probe task

Attentional bias to fear-relevant animals was assessed in 69 participants not preselected on self-reported anxiety with the use of a dot probe task showing pictures of snakes, spiders, mushrooms, and flowers. Probes that replaced the fear-relevant stimuli (snakes and spiders) were found faster than probes that replaced the non-fear-relevant stimuli, indicating an attentional bias in the entire sample. The bias was not correlated with self-reported state or trait anxiety or with general fearfulness. Participants reporting higher levels of spider fear showed an enhanced bias to spiders, but the bias remained significant in low scorers. The bias to snake pictures was not related to snake fear and was significant in high and low scorers. These results indicate preferential processing of fear-relevant stimuli in an unselected sample.

Correcting for numerator/denominator bias when assessing changing inequalites in occupational class mortality, Australia 1981-2002

Objective Comparisons of the changing patterns of inequalities in occupational mortality provide one way to monitor the achievement of equity goals. However, previous comparisons have not corrected for numerator/denominator bias, which is a consequence of the different ways in which occupational details are recorded on death certificates and on census forms. The objective of this study was to measure the impact of this bias on mortality rates and ratios over time. Methods Using data provided by the Australian Bureau of Statistics, we examined the evidence for bias over the period 1981-2002, and used imputation methods to adjust for this bias. We compared unadjusted with imputed rates of mortality for manual/non-manual workers. Findings Unadjusted data indicate increasing inequality in the age-adjusted rates of mortality for manual/non-manual workers during 1981-2002, Imputed data suggest that there have been modest fluctuations in the ratios of mortality for manual/non-manual workers during this time, but with evidence that inequalities have increased only in recent years and are now at historic highs. Conclusion We found that imputation for missing data leads to changes in estimates of inequalities related to social class in mortality for some years but not for others. Occupational class comparisons should be imputed or otherwise adjusted for missing data on census or death certificates.

Examination of emotional priming among children and young adolescents: Developmental issues and its association with anxiety

An affective priming task was used to examine bias in the processing of threat-related material in 25 clinically anxious compared to 25 matched, non-anxious control children and young adolescents. No significant differences were found between anxious and non-anxious children in terms of priming effects. However, age-related differences were found depending upon the valence of the target, independent of anxiety status. Both younger (7-10 years) and older (11-14 years) children showed faster response times to pleasant targets when they were preceded by a congruent compared to incongruent stimulus, consistent with a traditional priming effect. For threat target stimuli, older children showed no difference in response latency according to the congruency of the prime-target valence. Younger children, in contrast, showed a reverse priming effect for threat target stimuli, with slower response times for threat-congruent trials than for threat targets preceded by a pleasant prime. Possible explanations for developmental differences in the processing of threat-related material are discussed.

Obsessive-compulsive disorder across developmental trajectory: Cognitive processing of threat in children, adolescents and adults

Background. While the cognitive theory of obsessive-compulsive disorder (OCD) is one of the most widely accepted accounts of the maintenance of the disorder in adults, no study to date has systematically evaluated the theory across children, adolescence and adults with OCD. Method. This paper investigated developmental differences in the cognitive processing of threat in a sample of children, adolescents and adults with OCD. Using an idiographic assessment approach, as well as self-report questionnaires, this study evaluated cognitive appraisals of responsibility, probability, severity, thought-action fusion (TAF), thought-suppression, self-doubt and cognitive control. It was hypothesised that there would be age related differences in reported responsibility for harm, probability of harm, severity of harm, thought suppression, TAR self-doubt and cognitive control. Results. Results of this study demonstrated that children with OCD reported experiencing fewer intrusive thoughts, which were less distressing and less uncontrollable than those experienced by adolescents and adults with OCD. Furthermore, responsibility attitudes, probability biases and thought suppression strategies were higher in adolescents and adults with OCD. Cognitive processes of TAF, perceived severity of harm, self-doubt and cognitive control were found to be comparable across age groups. Conclusions. These results suggest that the current cognitive theory of OCD needs to address developmental differences in the cognitive processing of threat. Furthermore, for a developmentally sensitive theory of OCD, further investigation is warranted into other possible age related maintenance factors. Implications of this investigation and directions for future research are discussed.

Bias, precision and heritability of self-reported and clinically measured height in Australian twins

Many studies of quantitative and disease traits in human genetics rely upon self-reported measures. Such measures are based on questionnaires or interviews and are often cheaper and more readily available than alternatives. However, the precision and potential bias cannot usually be assessed. Here we report a detailed quantitative genetic analysis of stature. We characterise the degree of measurement error by utilising a large sample of Australian twin pairs (857 MZ, 815 DZ) with both clinical and self-reported measures of height. Self-report height measurements are shown to be more variable than clinical measures. This has led to lowered estimates of heritability in many previous studies of stature. In our twin sample the heritability estimate for clinical height exceeded 90%. Repeated measures analysis shows that 2-3 times as many self-report measures are required to recover heritability estimates similar to those obtained from clinical measures. Bivariate genetic repeated measures analysis of self-report and clinical height measures showed an additive genetic correlation > 0.98. We show that the accuracy of self-report height is upwardly biased in older individuals and in individuals of short stature. By comparing clinical and self-report measures we also showed that there was a genetic component to females systematically reporting their height incorrectly; this phenomenon appeared to not be present in males. The results from the measurement error analysis were subsequently used to assess the effects of error on the power to detect linkage in a genome scan. Moderate reduction in error (through the use of accurate clinical or multiple self-report measures) increased the effective sample size by 22%; elimination of measurement error led to increases in effective sample size of 41%.