Here's a few nice quotes on the value of peer review and publication from the Daubert Uncensored blog:
"Another pertinent consideration is whether the theory or technique has been subjected to peer review and publication. Publication (which is but one element of peer review) is not a sine qua non of admissibility; it does not necessarily correlate with reliability, and in some instances well-grounded but innovative theories will not have been published. Some propositions, moreover, are too particular, too new, or of too limited interest to be published. But submission to the scrutiny of the scientific community is a component of “good science,” in part because it increases the likelihood that substantive flaws in methodology will be detected. The fact of publication (or lack thereof) in a peer reviewed journal thus will be a relevant, though not dispositive, consideration in assessing the scientific validity of a particular technique or methodology on which an opinion is premised."
"But how do these considerations affect the admissibility analysis? Significantly. Experts testifying in large-scale litigation are usually leaders in their field—when the outcome depends upon compelling expert testimony, parties ordinarily retain first-string experts. Challenging the experts’ qualifications will almost always be futile, so focusing on peer review and publication will strengthen any challenge to the testimony."
“The ultimate test of a scientific expert’s integrity is her readiness to publish and be damned.”
"Haller v. AstraZeneca Pharm. LP, 598 F.Supp.2d 1271, 1296-97 (M.D. Fla. 2009). See generally Kumho Tire, 526 U.S. at 152 (holding that Daubert standards are intended “to make certain that an expert, whether basing testimony upon professional studies or personal experience, employs in the courtroom the same level of intellectual rigor that characterizes the practice of an expert in the relevant field”)."
"Expert witnesses are quick to spew litigation opinions as clear, compelling, beyond doubt, and a no-brainer, when they would never dare to submit those same opinions to the scrutiny of their peers. The experts’ unwillingness to subject opinions to peer review and publication speaks volumes about the scientific reliability of the analyses and conclusions."