From Am. Honda Motor Co. v. Allen, 600 F.3d 813 (7th Cir. 2010):
We hold that when an expert's report or testimony is critical to class certification, as it is here, ... a district court must conclusively rule on any challenge to the expert's qualifications or submissions prior to ruling on a class certification motion. That is, the dist ...
From Am. Honda Motor Co. v. Allen, 600 F.3d 813 (7th Cir. 2010):
We hold that when an expert’s report or testimony is critical to class certification, as it is here, … a district court must conclusively rule on any…