In the old days, before people had to figure out how Daubert is pronounced (the family in the litigation pronounces it “Dobbert”, so you can be all French and everything, but you’d be all wrong too – and I say that as a French major), experts simply said what they said, and if the expert’s opinions were that poor, the jury not only disregarded them after the expert had been destroyed on cross, but punished the rest of your case too for presuming to waste their time with such awful testimony. Of course if your expert presenting the termite-ridden opinions was better than the lawyer cross examining them, things got interesting, but we’re not going to talk about George Greene right now.
One of the interesting things about damages testimony, specifically in patent cases, is that since the Federal Circuit has ruled certain economic calculations out as a matter of law for various reasons, the inquiry when determining whether a damages expert can testify as to an opinion at trial is not always simply that the flaws in the opinions go to the weight (with the experienced trial judge knowing that the system tends to be self-correcting because flawed opinions tend to kick harder than they shoot) but sometimes whether the opinion itself is legally impermissible under controlling caselaw.
The attached is a recent opinion out of Tyler where some of these allegations were levelled against a couple of experts, and the Court’s analysis provided hopefully some useful discussion of when flaws in the expert’s opinion fall on weight side of the scale, as opposed to admissibility. The point above – that bad opinions don’t do well at trial – may have been the lesson from this case as well.