Daubert Happens.

Lest any of you forget that whole "gatekeeping thing," the 11th reminds us by affirming Judge Moore in a case where an otherwise well-respected, accomplished, and qualified expert offered an opinion that was not deemed reliable either as to general or specific causation.

Here's a key passage on the expert's flawed "differential diagnosis" methodology:

Kilpatrick is correct that differential diagnosis itself has been recognized as a valid and reliable methodology. But that is not the issue about which the district court found fault. Rather, the district court found that Dr. Poehling’s application of this methodology was flawed. In order to correctly apply this methodology, Dr. Poehling must have complied a comprehensive list of potential causes of Kilpatrick’s injury and must have explained why potential alternative causes were ruled out. However, Dr. Poehling only ruled out two causes – thermal energy and gentian violet contrast dye. He clearly testified that he could not explain why potentially unknown, or idiopathic alternative causes were not ruled out. Dr. Poehling also admitted that neither he nor anyone else in the medical community “understands the physiological process by which [chondrolysis] develops and what factors cause the process to occur.” Thus, the key foundation for applying differential diagnosis was missing, and based on these deficiencies, the district court found that Dr. Poehling failed to apply the differential diagnosis methodology reliably.

Why doesn't the darn doc just do some good, old-fashioned epidemiological studies?

Oh yeah, there is this:

Kilpatrick’s argument that conducting any epidemiological studies would be unethical, because it would require the potential destruction of a person’s shoulder cartilage, has some merit.

I'm not seeing the problem.