%0 Journal Article
%T Checklist for the qualitative evaluation of clinical studies with particular focus on external validity and model validity
%A Gudrun Bornh£¿ft
%A Stefanie Maxion-Bergemann
%A Ursula Wolf
%A Gunver S Kienle
%A Andreas Michalsen
%A Horst C Vollmar
%A Simon Gilbertson
%A Peter F Matthiessen
%J BMC Medical Research Methodology
%D 2006
%I BioMed Central
%R 10.1186/1471-2288-6-56
%X The checklist was developed by listing the most commonly used assessment criteria for clinical studies. Additionally, specific lists for individual applications were included. The categories of biases of internal validity (selection, performance, attrition and detection bias) correspond to structural, treatment-related and observational differences between the test and control groups. Analogously, we have extended these categories to address external validity and model validity, regarding similarity between the study population/conditions and the general population/conditions related to structure, treatment and observation.A checklist is presented, in which the evaluation criteria concerning external validity and model validity are systemised and transformed into a questionnaire format.The checklist presented in this article can be applied to both planning and evaluating of clinical studies. We encourage the prospective user to modify the checklists according to the respective application and research question. The higher expenditure needed for the evaluation of clinical studies in systematic reviews is justified, particularly in the light of the influential nature of their conclusions on therapeutic decisions and the creation of clinical guidelines.It is known that clinical studies can generate discordant results. This observation is addressed scientifically in various ways. Deviant study results may be understood as an expression of spreading or scattering from a supposed true value (whereas deviation depends on the precision of the methods). An alternative approach is to explain differences not statistically but by way of content [1]. In considering individual studies, there should be an estimate to what extent the study conclusions are distorted by systematic factors of bias. Here the focus lies usually on so called internal validity, the comparability of test and control groups. (Detailed definitions of internal validity and other validity categories are given
%U http://www.biomedcentral.com/1471-2288/6/56