What should I tell the other side before mediation?
How much information you disclose prior to mediation depends on your case and the status of the parties on the other side. Normally you want the other side to know about the strengths of your case so that they can evaluate their risks before the mediation.
This is particularly true if you are dealing with a corporate risk manager or insurance company as they will need this information prior to mediation in order to present it to their managers or loss committee. It is rare for a risk manager or insurance representative to have complete, unfettered authority and therefore if you blindside them with a significant piece of information at mediation that significantly increases the value of your case, it will often lead to a continuance or impasse if they are unable or unwilling to obtain additional authority.
It is more difficult for a claims representative to go back for more money since they have to first admit that their initial evaluation was wrong. Some adjusters would rather lose at trial and blame the result on the jury (or the lawyer), rather than risk their reputation or job by admitting to their boss that their initial assessment was wrong.