Nübling et al. BMC Public Health 2010, 10:428 http://www.biomedcentral.com/1471-2458/10/428 more hours), mobbing (more frequent in full time work- ers), general health and burnout (both being better for those working only up to 15 hours). Considering all aspects the relation was strongest for quantitative demands and quantity of social relations. Discussion and Conclusion Psychosocial factors at work were assessed using the theory-based and well established German version of the COPSOQ in 36 institutions in two sectors of geria- tric care: HC and GNH. Psychosocial work load in HC and GNH was com- pared to reference value of nurses in hospitals in the COPSOQ database and to the COPSOQ overall mean value across all professions. In a second step the influence of working hours per week and on-call duties on the evaluation of psychoso- cial factors was analyzed. One of the main findings was that especially in HC and partly also in GNH the psychosocial workload was evaluated as being lower than in general hospital care by the employees; however this seemed partly to be due to the high rate of part-time workers in HC. The response rate had a wide range from 11% up to 93% between the 36 institutions in the study - the over- all response in the study of 33% is a limitation. From our experience the participation rate is highly dependent on the level of motivation and activation achieved by the local contact persons promoting the survey in the orga- nization - however we have no information about this process for our study. A low response rate might lead to a lack of representativeness and introduce bias into the results. However, distribution of gender (88% females overall, 93% in HC and 83% in GNH) and the percentage of full time work (43% overall, 31% in HC and 61% in GNH) show that our sample is similar to other findings: Dulon and colleagues [21] found a full time rate of 31% in HC and 53% in nursing homes and a percentage of 90% female workers in HC and 87% in geriatric nursing homes in their study carried out in Germany. The inter- active GENESIS-online database of the German Federal Statistical Office https://www-genesis.destatis.de/genesis/ online gives for 2009 and for the whole branch of health and social care (no specific data on geriatric care avail- able) a rate of 35% full time workers and 80% female employees. Regarding the psychosocial factors at work the study produced some results that were expectable, for example the clearly superior rating of the aspect “meaning of work”, which is typical for all “helping professions” and has been demonstrated in many other national surveys (e.g. ALLBUS; Allgemeine Bevölkerungsumfrage in den Sozialwissenschaften/German General Social Survey), Page 9 of 12 international surveys (e.g. ISSP, International Social Sur- vey Programme), and studies on hospital workers (e.g. Aust et al. [22], applying the COPSOQ too). The assumption behind this is that the original motivation for the choice of a profession continues to be reflected in the later evaluation of the profession’s (positive) characteristics. Additionally, the study confirmed a phenomenon known from other COPSOQ surveys but up to now not completely explained, namely, the exceptionally positive ratings for “Quality of Leadership” and “Feedback” in the nursing professions. The ranking in the evaluation of quality of leadership - HC, followed by GNH and Hospital Care - was con- firmed in the NEXT study [23] as well. Theoretically, however, quality of leadership and feed- back are not aspects one would expect to see distributed according to occupational group, but according to the specific workplace situation (that is, they are not job- related, but workplace-related). This often found higher rating in the nursing professions may correspond to the fact that the questionnaire asks for a rating of the direct supervisor and that employees tend to experience their direct leaders more as a colleague with some leadership task than a distinct leader (especially since this position is often held by a former colleague). On a general level, the study also produced some sur- prising results, for example the rather positive ratings for the “quantitative demands” compared to nurses in general hospital care and the overall mean of all occupa- tions: study results were about average for GNH and markedly below average for HC employees. Previous studies [12,14,15], on the contrary, point to a high level of quantitative demands, e.g. time pressure, in the nursing professions. These studies, however, offer no comparison with other occupational groups, which would have made it possible to analyze the reported high level of quantita- tive demands with reference to external benchmark values. Several interpretations are possible: 1. Employees in nursing professions might be, on the whole, “less apt to complain”, that is, they might “subjectively” report the “objectively” very high demands as being lower than people in other occu- pations and thus give a value on or below the aver- age, even if the real demands are above. A predisposition or collective reinterpretation of this kind, however, would have to show evidence in the other scales as well, which does not appear to be the case. 2. Over the past decades general changes in working conditions could have led to an overall increase in