OBJECTIVES This work aims to develop a methodology for determining the qualitative composition of an expert group for the purpose of participation in decision-making in health care technology. Its goal is also to evaluate the methodology based on an example of the selection of large medical equipment. METHODS The complex weighting factor is a comprehensive evaluation of an expert. It is based on the expert’s overall work experience, experience in solving tasks, level of education and scientific record, interest in solving the particular task, current position, and awareness of how to solve the task. Also taken into account are the relevance of the expert’s knowledge and the overall self-evaluation concerning his or her total competence in solving the task. For the purpose of validating the methodology, 96 potential experts were interviewed. These subjects included managers from relevant departments in hospitals and hospital staff members who were from 72 health facilities in the Czech Republic. RESULTS Unlike the other models, the calculation model that was selected is able to eliminate errors in estimating the proportionality of extreme values and to reduce the impact of uncertainty in the experts’ overall self-evaluations concerning their total competence to the combined ratio. Based on this model, a methodology for selecting experts was developed. A statistically significant correlation was found between the complex weighting factor and the following characteristics: the expert's experience in dealing with similar tasks (r=0.512, p<0.001), the expert's theoretical background (awareness) and the relevance of the expert's knowledge (r=0.44, p<0.001), the expert´s current position (r=0.319, p=0.002), and the level of his or her education and scientific record (r=0.28, p=0.007).  CONCLUSIONS This methodology will be especially useful in scientific and technological forecasting, medical and managerial decision-making, quality assessment, and operational research.