The Rand Institute for Civil Justice reports that there is “little hard evidence” to support arguments made by proponents or opponents of proposals allowing lawsuits against private, employer-sponsored health plans.

Lawmakers on both sides of the sue-your-HMO issue have starkly different views about the effects of such a change, according to the Rand report. So researchers at the institute, a division of the Rand Corp., examined the main assumptions underlying support and opposition: