BackgroundThe quality of decision-making in multidisciplinary team meetings (MDTMs) depends on the quality of information presented and the quality of team processes. Few studies have examined these factors using a standardized approach. The aim of this study was to objectively document the processes involved in decision-making in MDTMs, document the outcomes in terms of whether a treatment recommendation was given (none vs. singular vs. multiple), and to identify factors related to type of treatment recommendation.MethodsAn adaptation of the observer rating scale Multidisciplinary Tumor Board Metric for the Observation of Decision-Making (MDT-MODe) was used to assess the quality of the presented information and team processes in MDTMs. Data was analyzed using descriptive statistics and mixed logistic regression analysis.Results N = 249 cases were observed in N = 29 MDTMs. While cancer-specific medical information was judged to be of high quality, psychosocial information and information regarding patient views were considered to be of low quality. In 25% of the cases no, in 64% one, and in 10% more than one treatment recommendations were given (1% missing data). Giving no treatment recommendation was associated with duration of case discussion, duration of the MDTM session, quality of case history, quality of radiological information, and specialization of the MDTM. Higher levels of medical and treatment uncertainty during discussions were found to be associated with a higher probability for more than one treatment recommendation.ConclusionsThe quality of different aspects of information was observed to differ greatly. In general, we did not find MDTMs to be in line with the principles of patient-centered care. Recommendation outcome varied substantially between different specializations of MDTMs. The quality of certain information was associated with the recommendation outcome. Uncertainty during discussions was related to more than one recommendation being considered. Time constraints were found to play an important role. Some of those aspects seem modifiable, which offers possibilities for the reorganization of MDTMs.Electronic supplementary materialThe online version of this article (10.1186/s12885-017-3768-5) contains supplementary material, which is available to authorized users.