https://www.americanbar.org/content/dam/aba/administrative/dispute_resolution/materials/2019-mediation-research-task-force-report.pdf

This report (summarized here) looked at 50 studies that examined the effect of mediator techniques and actions on (1) settlement and related outcomes; (2) disputants’ relationship or ability to work together and their perceptions of the mediator, the mediation process or the outcome; and (3) the attorneys’ perceptions of the mediation. Because the studies defined mediator techniques and actions differently, the report organized them into categories. When looked at as a whole, the studies were mixed in their findings regarding the effect of particular categories of techniques on outcomes. Thus, the studies provide no clear guidance about which techniques will have a positive effect on outcomes and which will be detrimental. However, four categories of techniques were found to have the potential to increase the probability of settlement and improve party relationships and perception of the mediation: eliciting disputants’ suggestions or solutions; giving more attention to disputants’ emotions, relationships, and sources of conflict; working to build trust and rapport, expressing empathy or praising the disputants, and structuring the agenda; and using pre-mediation caucuses focused on establishing trust.