RÉSUMÉ
AIM: Multimodal treatment strategies make the assessment of health care services very difficult even for experts and almost impossible for lay persons. The aim of this project was to present complex data from scientific publications in a simplified way so that all essential information is preserved, but still assessable by lay persons and to compare their assessments with the recommendations of experts. METHODS: Using the surgical treatment of rectal cancer with or without preoperative radiation as an example, the aims of treatment as well as the "outcomes" (actually intended study endpoints) and "outputs" (surrogate parameters) were defined, identified and presented graphically for five key studies of neoadjuvant treatment. RESULTS: German lay persons (n = 59) favoured in the majority of the cases (93 %) surgical treatment without preoperative radiation. Lay persons assessed the results in a similar manner to other groups (physicians, health care workers, and health care politicians) and lay persons of other cultural backgrounds. Altogether, the participants (n = 152) favoured surgical treatment without preoperative therapy in 86 % of the cases (653 of 760). This lay assessment did not correlate with the assessments and recommendations of the scientific societies responsible for the guidelines. CONCLUSIONS: Complex scientific results can be prepared in such a way that their assessment by lay persons is feasible. Lay persons orientate their assessment according to the outcomes, while the recommendations of the guidelines are more directed by the outputs. These different viewpoints should be taken more into consideration for the development of guidelines than they are now.