This goes to the heart of mediation. Mediators are not there to make a decision like a judge or arbitrator and this is the key difference from those processes. The parties have to do work hard in mediations to make their own decisions.
This is the opportunity presented by mediation to parties that they can retain control of their dispute. It enables the people who have the most interest in the outcome and who know the dispute best have the chance to formulate a solution.
Although the parties may present information during the mediation, mediation practice does not encourage the parties to present evidence as they would in a court case. The reason for presenting their perspective is based on communication and understanding rather than as forming an evidential basis for negotiations.