It’s important to bear in mind that experts have a different function at the PTAB than they do in district court; they’re presented in a different way. Their testimony comes in writing, initially as a written declaration of sworn testimony and then cross examination comes in through deposition. Oftentimes during a post AIA-review, the merit arguments will turn on claim construction issues and an expert becomes crucial in that regard.
The PTAB judges have the ability to draw on their own technical backgrounds to determine whether what they’re hearing from the expert rings true. That means the credibility determination is one that they are more willing to make than fact finders in district court.
In view of attacking expert credibility, the deposition of that expert takes on a whole new level of importance. It is very important during the deposition to push that expert to sometimes very extreme positions.
Oftentimes experts can find themselves in a surprising place and the board is quite savvy about determining where someone is within their qualifications and where they’re not. If an expert is too extreme, their credibility can be put at risk and one side could get some good testimony that can be quoted before the PTAB to show that the expert has gone beyond common sense and logic.
Above all, it’s important to assess what an expert can accomplish and one of the things that’s important to bring to bear is what is special about an individual case and what is the expert going to add to what the board already knows and what the record already shows.