This study examines a basic assumption of peer review, namely, the idea that there is a consen- sus on evaluation criteria among peers, which is a necessary condition for the reliability of peer judgements. Empirical evidence indicating that there is no consensus or more than one consen- sus would offer an explanation for the disagreement effect, the low inter-rater reliability consist- ently observed in peer review. To investigate this basic assumption, we have surveyed all humanities scholars in Switzerland on 23 grant review criteria. We have employed latent class tree modelling to identify subgroups in which scholars rated criteria similarly (i.e. latent classes) and to explore covariates predicting class membership. We have identified two consensus classes, two consensus-close classes, and a consensus-far class. The consensus classes contain a core consensus (10 criteria related to knowledge gaps; feasibility; rigour; comprehensibility and argumentation; academic relevance; competence and experience of the applicant) and a broad consensus that include the core consensus plus eight contribution-related criteria, such as originality. These results provide a possible explanation for the disagreement effect. Moreover, the results are consistent with the notion of conservatism, which holds that original research is undervalued in peer review, while other aspects, such as methodology and feasibility, are over- weighted. The covariate analysis indicated that age and having tenure increase from the consen- sus far to the consensus close to the consensus classes. This suggests that the more academic experience scholars accumulate, the more their understanding of review criteria conforms to the social norm.