Sonrai Systems, LLC et al v. Anthony M. Romano et al, 1:16-cv-03371

Sonrai Systems, LLC sued Anthony Romano and The Heil Co. (Environmental Solutions Group) for allegedly interfering with Sonrai’s business, causing lost customer contracts and profits.
Sonrai engaged expert Suzanne Stuckwisch to calculate lost profits, who produced several expert reports over multiple years adjusting her lost profits estimate in response to legal developments and court rulings, finally reaching $83.4 million.
Defendants moved to exclude Stuckwisch’s testimony under Rule 702 (Daubert motion), contending her lost profits methodology and assumptions were unreliable.
The court previously struck part of Stuckwisch’s damages analysis (additional incremental operation costs) but permitted report supplementation and further deposition/discovery on damages.
Judge Thomas M. Durkin held hearings, reviewed evidence, and ultimately had to determine if Stuckwisch’s testimony met the admissibility standards of Rule 702.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Methodology (lost profits)	Used accepted "before-and-after" approach per AICPA standards	Did not follow a reliable, established methodology	Stuckwisch applied accepted methodology reliably; admissible
Basis for fleetwide rollout assumption	Commitment and evidence from third parties and market research	No evidence or insufficient corroboration for rollouts	Supported by evidence; factual basis to be weighed by jury
Consideration of alternative causes	Calculated damages on customer-by-customer basis; Jury can assess causation	Used "all-or-nothing" approach, failed to account for other causes (e.g. Geotab, Sonrai's own conduct)	Approach reasonable; causation criticisms go to weight, not admissibility
Deduction of incremental operation costs	Costs have been disclosed; included when permitted	Excluded costs in latest report, making calculation unreliable	Remedy is supplementation, not exclusion; defendants not prejudiced

Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579 (gatekeeping for expert testimony—focus on methodology, not conclusions)
Manpower, Inc. v. Insurance Co. of Pennsylvania, 732 F.3d 796 (7th Cir. 2013) (court should focus on validity of expert methodology, not data or conclusions)
Stollings v. Ryobi Technologies, Inc., 725 F.3d 753 (7th Cir. 2013) (expert must use valid methodology and apply it appropriately)
United States v. Hill, 818 F.3d 289 (7th Cir. 2016) (courts have broad latitude to evaluate expert testimony)
Schultz v. Akzo Nobel Paints, LLC, 721 F.3d 426 (7th Cir. 2013) (no need for expert to rule out all alternative causes)