Walter Olson at Point of Law shares a study from the Pacific Research Institute on the effect of various tort reforms. The study, was authored by Nicole V. Crain, W. Mark Crain, Lawrence J. McQuillan, and Hovannes Abramyan, and is titled "Tort Law Tally: How State Tort reforms affect Tort Losses and Tort Insurance Premiums".
Here is an excerpt from the executive summary:
Of the 25 tort reforms that we examine, the statistical analysis identifies 18 reforms to state civil-justice systems that significantly reduced tort losses and tort insurance premiums from 1996 through 2006. For some categories of tort cases, specific reforms cut payouts by more than 50 percent. The cumulative effect of reforms across all tort categories is a 47-percent reduction in losses and a 16-percent reduction in insurance premiums for consumers. Some tort reforms are highly effective at reducing costs in certain tort categories, but are ineffective in other tort categories. It is important that reformers pick the right tool for each problem. If we order the tort reforms according to each reform’s ability to reduce aggregate tort losses, the top eight reforms are: attorney-retention sunshine (12 percent), Daubert/Frye (10 percent), frivolous lawsuits (7 percent), jury service (6 percent), appeal-bond caps (4 percent), negligence standard (3 percent), non-economic-damage caps (2 percent), and medical-malpractice damage caps (1 percent).
Thanks to Torts Prof for alerting me about the paper.