"The number of court filings are virtually meaningless as a measure of civil justice system outcomes," Mr. Corum said. "The frequency of court filings is determined, in large part, by the criteria and methods plaintiff attorneys use to decide whether to accept a case."

Mr. Corum added that, in recent years, plaintiff attorneys have become more sophisticated in judging whether a case is likely to end with a favorable settlement. "The number and size of costly settlements could very easily be rising as the number of court filings declines," he said.

Furthermore, Mr. Corum said, "the number of trials also tells us very little about final civil justice system outcomes." In fact, he adds, "as the risk of actually going to trial increases, with higher verdicts and an increased risk of a very large verdict, it should not be surprising if fewer cases go to trial because the incentive to settle a case before trial increases."

Mr. Corum said that incurred medical malpractice claim losses in Illinois, over the period 2000-2004, increased 60 percent, from $322 million to $517 million, citing A.M. Best data. "Common sense suggests that if one wanted to know why insurance premium costs have risen significantly in recent years, the place to look for an answer would be the claim losses actually incurred by insurance carriers," explained Corum.

"The Vidmar report fails to acknowledge this basic fact or review the available data on incurred claim losses, and, therefore, fails to provide a useful explanation of recent changes in insurance prices," he said.

The Duke study is one of several recent findings that civil litigation is not the driving force behind medical malpractice rates that advocates of legal changes in the system say it is.

On May 17, Washington, D.C.-based Economic Policy Institute released a study by economist Lawrence Chimerine and attorney Ross Eisenbrey who reported their research found no indication that imposing tort reform measures would create an economic benefit.

"Instead, our analysis shows that the so-called tort litigation crisis is based on wildly overstated cost estimates that have been wildly cited by lawmakers and the media as support for calls for legal change," said a spokesperson for the Washington-based Institute.