Many advantages are attributed to participatory enterprise modelling as compared to conventional modelling and elicitation approaches. Among them are an improved quality of the models, better acceptance of the modelling results by the stakeholders and co-creation of models by different stakeholders. Although these advantages were observed in a number of modelling projects, there is not much empirical work comparing conventional and participatory modelling in real-world cases. Much work on participatory modelling is more exploratory and argumentative than explanatory and conclusive. From a pragmatic perspective, one effect of this situation is missing decision criteria when to do participatory and when conventional modelling. This paper aims at contributing to this research area by investigating what factors should be taken into account when deciding for or against participatory enterprise modelling. The approach taken is to analyze successful and non-successful cases from both participatory and conventional modelling in order to identify such decision factors. The main contributions of this paper are (1) an approach for analyzing enterprise modelling cases consisting of criteria derived from literature on enterprise modelling, (2) comparison of conventional and participatory modelling cases according to the analysis criteria and (3) a detailed discussion of criteria relevant for the decision for/against participatory or conventional modelling