The dispute over whether litigants may use experts to run unexamined hearsay into the trial record is a microcosm of a larger debate. The larger question is whether judicial review of expert testimony should be passive, or whether the expert witness process should be marked by active judicial policing. Does the plethora of expert opinions presently being offered in modern trials merit special scrutiny by the courts?

Some scholars urge that courts must accommodate experts. Proponents of this view favor few challenges to the unrestricted rendition of opinions by an expert, whether the expert is real or self-proclaimed. Under this approach, "[a]s long as the expert testified that he was qualified, that the data he used was of the type reasonably relied upon by other experts in the field, and that he was reasonably certain of his conclusions, judges would present the evidence to the jury without further scrutiny." A passive judicial approach to expert testimony facilitates ready admission of the underlying data used by an expert to reach her conclusions. It means that rigorous application of hearsay doctrine, requiring that the author of the underlying hearsay document be present or at least have been cross-examined, is abandoned.

A growing number of courts and commentators have criticized the passive approach to expert testimony. Some have urged strict control of runaway expert testimony. For example, the United States Court of Appeals for the Fifth Circuit has remarked: "It is time to take hold of expert testimony in federal trials." To this end, Minnesota amended its evidence rules to embrace a policy prohibiting, on direct examination, the wholesale introduction of the background documents used by an expert to reach his or her conclusions.

Which view is preferable? Which addresses modern pressures and current courtroom conditions? Should judges play an active role in policing expert testimony? This Article endeavors to resolve these issues, and suggests a solution to the problem of backdoor hearsay through expert opinion.