In Daubert v. Merrell Dow Pharmaceuticals, 509 U.S. 579 (1993), the U.S. Supreme Court held that four factors should be used by courts to see if an expert’s proposed opinions were reliable: 1) if the theory can be and has been tested; 2) if it has been subject to peer review or publication; 3) whether the known or the potential rate of error is acceptable; and 4) if the opinion has received general acceptance by the scientific community.
On remand, Daubert v. Merrell Dow Pharmaceuticals, 43 F.3d 1311 (1995) (Daubert II), the 9th Circuit commented that “one very significant fact” is whether an expert is proposing to testify about matters growing naturally and directly out of research he has conducted independent of the litigation or whether the opinion was developed expressly for the purposes of testifying. The 9th Circuit believed that research “conducted independent of the litigation provides important objective proof that the research comports with the dictates of good science” and findings that flow from it are less likely to have been biased toward a particular conclusion by the promise of remuneration.
