In both legal and political settings there has been a push toward adopting institutions that encourage consensus. The key feature of these institutions is that they bring interested parties together to communicate with each other. Existing research about the success or failure of particular institutions is ambiguous. Therefore, we turn our attention to understanding the general conditions when consensus is achievable, and we test experimentally three crucial factors that affect a group’s ability to achieve consensus: (1) the difficulty of the problem, (2) the costs of communication, and (3) the structure of communication. Using multiple experimental approaches, we find that difficult problems impede consensus, costs make consensus less likely (even relatively very small costs), and the structure of communication has significant effects and interacts with both problem difficulty and costs. In particular, the structure of communication can reduce the negative effect of costs and facilitate consensus. Together these results imply that consensus is only likely to occur if problems are easy, costs to communicate are low, or the communication structure helps overcome the other two problems. These findings can provide insight about the institutional designs that can be utilized to promote consensual outcomes.