Handling missing data by re-approaching non-respondents

When handling missing data, a researcher should be aware of the mechanism underlying the missingness. In the presence of non-randomly missing data, a model of the missing data mechanism should be included in the analyses to prevent the analyses based on the data from becoming biased. Modeling the missing data mechanism, however, is a difficult task. One way in which knowledge about the missing data mechanism may be obtained is by collecting additional data from non-respondents. In this paper the method of re-approaching respondents who did not answer all questions of a questionnaire is described. New answers were obtained from a sample of these non-respondents and the reason(s) for skipping questions was (were) probed for. The additional data resulted in a larger sample and was used to investigate the differences between respondents and non-respondents, whereas probing for the causes of missingness resulted in more knowledge about the nature of the missing data patterns

The evaluation of the Center for Epidemiologic Studies Depression (CES-D) scale: depressed and positive affect in cancer patients and healthy reference subjects

This study examined the reliability and validity of a two-factor structure of the Center for Epidemiologic Studies Depression (CES-D) scale. The study was conducted in a large group of cancer patients (n = 475) and a matched reference group (n = 255). Both groups filled in a questionnaire at two points in time: patients 3 and 15 months after diagnosis. Factor analysis confirmed our hypothesis that the 16 negatively and four positively formulated items measure two relatively independent factors, i.e. Depressed Affect and Positive Affect. Therefore, these items should not be combined into an overall sumscore. In both groups, Depressed Affect proved to be a reliable and valid measure of depressive symptomatology, as indicated by its good internal consistency, its strong correlations with other measures of psychological distress and neuroticism, and its effectiveness in discriminating patients from the reference group on depressive symptomatology. In contrast, the validity of the Positive Affect factor could not be confirmed, since it was only weakly related to other measures of psychological distress and extraversion. Depressed and Positive Affect were about equally related to self-esteem, life satisfaction, and quality of life. These findings support the use of a sumscore based on the 16 negatively formulated CES-D items as a more valid measure of depressive symptomatology, in cancer patients and in healthy individuals from the general population

Het meten van sociale steun

In dit proefschrift wordt verslag gedaan van een onderzoek naar de conceptualisering en operationalisering van het begrip 'sociale steun'. In hoofdstuk 1 wordt beknopt de vraagstelling aangegeven, welke in drie delen uiteenvalt, te weten: (1) Wat kan op conceptueel niveau verstaan worden onder het begrip sociale steun, en hoe zijn de aspecten die onder dit begrip vallen onderling gerelateerd? (2) Hoe betrouwbaar en valide zijn de meetinstrumenten voor elk van de aspecten van sociale steun? (3) Bestaan er relaties tussen kenmerken van het sociaal netwerk enerzijds en de overige aspecten in het proces van ondersteuning anderzijds? Zie: Samenvatting

Statistical significant change versus relevant or important change in (quasi) experimental design: some conceptual and methodological problems in estimating magnitude of intervention-related change in health services research

Health-related functional status: concepts, measurement and psychometric propertie

Patient-reported outcome measures in community mental health teams: pragmatic evaluation of PHQ-9, GAD-7 and SWEMWBS.

Aims and method We evaluated routine use, acceptability and response rates for the Patient Health Questionnaire (PHQ-9), Generalised Anxiety Disorder Scale (GAD-7) and Short Warwick-Edinburgh Mental Well-Being Scale (SWEMWBS) within adult community mental health teams. Measures were repeated 3 months later. Professionals recorded the setting, refusal rates and cluster diagnosis. Results A total of 245 patients completed 674 measures, demonstrating good initial return rates (81%), excellent scale completion (98-99%) and infrequent refusal/unsuitability (11%). Only 32 (13%) returned follow-up measures. Significant improvements occurred in functioning (P = 0.01), PHQ-9 (P = 0.02) and GAD-7 (P = 0.003) scores (Cohen's d = 0.52-0.77) but not in SWEMWBS (P = 0.91) scores. Supercluster A had higher initial PHQ-9 and GAD-7 scores (P < 0.001) and lower SWEMWBS scores (P = 0.003) than supercluster B. Supercluster C showed the greatest functional impairment (P = 0.003). Clinical implications PHQ-9 and GAD-7 appear acceptable as patient-reported outcome measures in community mental health team. SWEMWBS seems insensitive to change. National outcome programmes should ensure good follow-up rates. Declaration of interest None