Martin Ostapczuk

Reducing socially desirable responses in epidemiologic surveys: an extension of the randomized-response technique.

Background: Even though the validity of self-reports of sensitive behaviors is threatened by social desirability bias, interviews and questionnaires are widely used in epidemiologic surveys on these topics. Methods: In the randomized-response technique, a randomization device is used to determine whether participants are asked to respond truthfully or whether they are prompted to provide a prespecified response. In this study, the randomized-response technique was extended by using a cheating-detection modification to obtain more valid data. The survey was on the dental hygiene habits of Chinese college students. Results: Whereas only 35% of men and 10% of women admitted to insufficient dental hygiene when questioned directly, 51% of men and 20% of women attested to this socially undesirable behavior in a randomized-response survey. Conclusions: Given the considerable discrepancy between the results obtained by direct questioning and by using the randomized-response technique, we propose that this technique be considered for use in epidemiologic studies of sensitive behaviors.

DREEM on, dentists! Students’ perceptions of the educational environment in a German dental school as measured by the Dundee Ready Education Environment Measure

OBJECTIVES The educational climate in which future doctors are trained is an important aspect of medical education. In contrast to human medicine, it has been rather neglected in dental educational research. The aim of the study was to supplement this lack by applying and validating the Dundee Ready Education Environment Measure (DREEM) for the first time in a German-speaking sample of dental students. METHODS All dental students at the Medical Faculty of Heinrich-Heine-University Düsseldorf were asked to complete a German adaptation of the DREEM and the Düsseldorf Mission Statement Questionnaire (DMSQ) in a paper-pencil survey. Data from 205 participants were analysed. Psychometric validation included analysis of item homogeneity and discrimination, test reliability, criterion and construct validity (convergent, factorial). RESULTS DREEM item parameters were satisfactory, reliability (α = 0.87) and convergent validity (r = 0.66 with DMSQ) were also high. Factor analyses, however, yielded dimensions which did not fully correspond to the original DREEM subscales. Overall perception of the educational environment was positive (DREEM total score = 122.95 ± 15.52). Students in the clinical part of course rated the atmosphere more negatively, but their academic self-perception more positively than preclinical students. CONCLUSIONS Showing satisfactory psychometric properties, DREEM proved suitable for assessing educational environments among dental students. Given the right circumstances, e.g., small and early clinically oriented classes, traditional curricula can generate positive environments.

Assessing Sensitive Attributes Using the Randomized Response Technique: Evidence for the Importance of Response Symmetry

Randomized response techniques (RRTs) aim to reduce social desirability bias in the assessment of sensitive attributes but differ regarding privacy protection. The less protection a design offers, the more likely respondents cheat by disobeying the instructions. In asymmetric RRT designs, respondents can play safe by giving a response that is never associated with the sensitive attribute. Symmetric RRT designs avoid the incentive to cheat by not allowing such responses. We tested whether a symmetric variant of a cheating detection model (CDM) increases compliance with the instructions in a survey of academic dishonesty among 2,254 Chinese students. As we observed more noncompliance in the asymmetric than symmetric variant, we recommend the use of symmetric CDMs, which can easily be tested within multinomial models.

Assessing the learning environment of a faculty: Psychometric validation of the German version of the Dundee Ready Education Environment Measure with students and teachers

Aims: The teachers’ perspectives of the educational environment have as yet only been sparsely considered. This study aimed at validating the first German version of the Dundee Ready Education Environment Measure (DREEM) from the points of view of both students and teachers. Methods: Data from 1119 students and 258 teachers were available for analysis. Psychometric validation included the analysis of homogeneity and discrimination at item level as well as reliability (Cronbachs α), criterion and construct validity at test level. Effect sizes were calculated and the independent samples t-test was used for statistical inference testing of mean differences between two groups. Results: Item characteristics were satisfactory in both samples. Reliability was high with α = 0.92 (students) and 0.94 (teachers), respectively. Factor analyses revealed five dimensions which slightly diverged from the five subscales postulated by the DREEM authors though. The environment was evaluated significantly (p < 0.001) more positively by teachers (M = 117.63) than by students (M = 109.75). Further significant differences were observed with regard to gender, mother language, stage of studies and previous professional training among others. Conclusions: With convincing psychometric properties at item and test levels, the suitability of DREEM not only for students but also for teachers to assess the educational environment has been demonstrated.

Improving self-report measures of medication non-adherence using a cheating detection extension of the randomised-response-technique

Medication non-adherence is a serious problem for medical research and clinical practice. Self-reports are only moderately valid, and objective methods are cumbersome and expensive to administer. We sought to improve self-reports of medication non-adherence using a cheating detection extension of the randomised-response-technique (RRT). This RRT variant encourages more honest responses by offering interviewees a higher degree of anonymity while simultaneously allowing us to estimate the proportion of respondents disobeying the RRT instructions. The 597 patients were asked to report their lifetime prevalence of medication non-adherence under one of two different questioning procedures, direct questioning or randomised-response. When questioned directly, only 20.9% of patients admitted to intentional medication non-adherent behaviour, as opposed to 32.7% of patients under RRT conditions. Additionally, the cheating detection extension revealed a significant proportion of patients (47.1%) disobeying the instructions in the RRT condition. Assuming that either none or all of them were non-adherent, a lower and upper bound of 32.7% and 79.8%, respectively, could be estimated for the lifetime prevalence of non-adherent behaviour. The results demonstrate that self-report measures as well as traditional variants of the RRT, which do not take cheating into account, may provide considerably distorted estimates of the prevalence of medication non-adherence.

Estimating the prevalence of negative attitudes towards people with disability: a comparison of direct questioning, projective questioning and randomised response

Purpose. Despite being susceptible to social desirability bias, attitudes towards people with disabilities are traditionally assessed via self-report. We investigated two methods presumably providing more valid prevalence estimates of sensitive attitudes than direct questioning (DQ). Most people projective questioning (MPPQ) attempts to reduce bias by asking interviewees to estimate the number of other people holding a sensitive attribute, rather than confirming or denying the attribute for themselves. The randomised-response technique (RRT) tries to reduce bias by assuring confidentiality through a random scrambling of the respondents answers. Method. We assessed negative attitudes towards people with physical and mental disability via MPPQ, RRT and DQ to compare the resulting estimates. Results. The MPPQ estimates exceeded the DQ estimates. Employing a cheating-detection extension of the RRT, we determined the proportion of respondents disregarding the RRT instructions and computed an upper bound for the prevalence of negative attitudes. MPPQ estimates exceeded this upper bound and were thus shown to overestimate the prevalence. Furthermore, we found more negative attitudes towards people with mental disabilities than those with physical disabilities in all three questioning conditions. Conclusions. We recommend employing the cheating-detection variant of the RRT to gain additional insight in future studies on attitudes towards people with disabilities.

A new treatment for hip osteoarthritis: clinical evidence for the efficacy of autologous conditioned serum

The purpose of the present study was to investigate the effect of intra-articular injections of autologous conditioned serum on human hip osteoarthritis and to test whether a potential treatment effect might be increased by additional injections of steroids and the recombinant interleukin-1 receptor antagonist protein anakinra. We compared the effects of autologous conditioned serum 46 hip osteoarthritis patients), autologous conditioned serum+cortisone (56 patients), and autologous conditioned serum+cortisone+recombinant interleukin-1 receptor antagonist protein (17 patients) in a retrospective clinical study by means of the Visual Analogue Scale for pain (pre- vs posttreatment). Over 14 months, treatment resulted in a large, statistically significant improvement for patients in all three groups, independent of the severity of osteoarthritis. Neither cortisone nor cortisone+recombinant interleukin-1 receptor antagonist protein increased the beneficial treatment effect over and above the effect of autologous conditioned serum alone. Autologous conditioned serum successfully reduces pain in hip osteoarthritis. In severe hip osteoarthritis, the sole application of autologous conditioned serum can be even more beneficial than the combination of autologous conditioned serum with steroids.

Validating an Inventory for the Assessment of Egoistic Bias and Moralistic Bias as Two Separable Components of Social Desirability

The psychometric properties of the German adaptation of the Balanced Inventory of Desirable Responding were investigated. This 2-factor inventory taps the egoistic bias and the moralistic bias as the 2 distinguishable components of social desirability. In 2 validation studies, both subscales showed satisfactory internal consistency and temporal stability. To examine convergent and discriminant validity, the scales were correlated with those of a measure of unrealistic optimism, various measures of self-enhancement, 1-dimensional scales of social desirability, and the tendency to overclaim in a test of general knowledge.

The influence of relative age on the composition of professional soccer squads.

Abstract Children born shortly after the cut-off date applying for age grouping in minor sports profit from being able to remain for almost an additional year in their respective age group compared to those born later in the same year. A shift of the cut-off date in German youth soccer in 1997 allowed us to investigate the effect of a favourable relative age as well as the effect of a change of the cut-off date on the birth-date distribution of soccer players in the Bundesliga (Division 1), the highest professional soccer league in Germany. Both the cut-off date and the change of the cut-off date exerted a significant influence on the composition of professional senior squads. In the 1997/98 season, there was an overrepresentation of players profiting from the old cut-off date of 1 August. In the 2007/08 season, 10 years after the change of the cut-off date, there was an overrepresentation of players born shortly after the new cut-off date of 1 January. This pattern of results shows that owing to the cut-off dates applying in youth soccer, the date of birth of young players systematically influences their later professional success and career.

Development and evaluation of a questionnaire to measure the perceived implementation of the mission statement of a competency based curriculum

BackgroundA mission statement (MS) sets out the long-term goals of an institution and is supposed to be suited for studying learning environments. Yet, hardly any study has tested this issue so far. The aim of the present study was the development and psychometric evaluation of an MS-Questionnaire (MSQ) focusing on explicit competencies. We investigated to what extent the MSQ captures the construct of learning environment and how well a faculty is following - in its perception - a competency orientation in a competency-based curriculum.MethodsA questionnaire was derived from the MS “teaching” (Medical Faculty, Heinrich-Heine University Düsseldorf) which was based on (inter-) nationally accepted goals and recommendations for a competency based medical education. The MSQ was administered together with the Dundee Ready Education Environment Measure (DREEM) to 1119 students and 258 teachers. Cronbach’s alpha was used to analyze the internal consistency of the items. Explorative factor analyses were performed to analyze homogeneity of the items within subscales and factorial validity of the MSQ. Item discrimination was assessed by means of part-whole corrected discrimination indices, and convergent validity was analyzed with respect to DREEM. Demographic variations of the respondents were used to analyze the inter-group variations in their responses.ResultsStudents and teachers perceived the MS implementation as “moderate” and on average, students differed significantly in their perception of the MS. They thought implementation of the MS was less successful than faculty did. Women had a more positive perception of educational climate than their male colleagues and clinical students perceived the implementation of the MS on all dimensions significantly worse than preclinical students. The psychometric properties of the MSQ were very satisfactory: Item discrimination was high. Similarly to DREEM, the MSQ was highly reliable among students (α = 0.92) and teachers (α = 0.93). In both groups, the MSQ correlated highly positively with DREEM (r = 0.79 and 0.80, p < 0.001 each). Factor analyses did not reproduce the three areas of the MS perfectly. The subscales, however, could be identified as such both among teachers and students.ConclusionsThe perceived implementation of faculty-specific goals can be measured in an institution to some considerable extent by means of a questionnaire developed on the basis of the institution’s MS. Our MSQ provides a reliable instrument to measure the learning climate with a strong focus on competencies which are increasingly considered crucial in medical education. The questionnaire thus offers additional information beyond the DREEM. Our site-specific results imply that our own faculty is not yet fully living up to its competency-based MS. In general, the MSQ might prove useful for faculty development to the increasing number of faculties seeking to measure their perceived competency orientation in a competency-based curriculum.