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  • Accident Reconstruction Expert Not Allowed to Opine on Statutory Violation

    Accident Reconstruction Expert Not Allowed to Opine on Statutory Violation

    On July 13, 2021, Mark DeLeon lost his left arm in a horrendous accident while working the overnight shift at Norfolk Southern’s Burns Harbor Trainyard. This case arises out of that tragic event. DeLeon sued Norfolk Southern under the Federal Employer’s Liability Act seeking recovery for his injuries. He has two theories under FELA: one is for general negligence; the other is for per se negligence under FELA because of an alleged violation of the Safety Appliance Act (“SAA”).

    Norfolk sought the exclusion of three of DeLeon’s experts-Daniel Billington, Colon Fulk, and Jason Engle.

    Accident Reconstruction Expert Witness

    Daniel R. Billington II is an expert in accident reconstruction, including “human factors, visibility, and lighting.” Billington has been doing accident reconstructions for decades and has been permitted to testify in a number of cases. His knowledge has made him a speaker in high demand with many legal and insurance organizations.

    Get the full story on challenges to Daniel Billington’s expert opinions and testimony with an in-depth Challenge Study.

    Railroad Expert Witnesses

    Colon Ray Fulk has over three decades of experience in train operations. Notably, he has worked for Norfolk as a conductor, brakeman, locomotive engineer, and a foreman. He has extensive experience in railroad operations, including safety inspections and investigations.

    Discover more cases with Colon Fulk as an expert witness by ordering his comprehensive Expert Witness Profile report.

    Jason R. Engle has 18 years of experience in the railroad industry, holding both mechanical and transportation positions at multiple railway companies.

    Get the full story on challenges to Jason Engle’s expert opinions and testimony with an in-depth Challenge Study.

    Discussion by the Court

    The Court agreed with Norfolk that the expert reports of Billington, Fulk, and Engle had some improper legal conclusions. Billington, Fulk, and Engle all stated that certain facts constitute a statutory violation and/or negligence. These conclusions “abridge the jury’s role of applying the law to the facts” and, additionally, “usurp the judge’s role of instructing the jury as to the applicable law.”

    The experts will not be allowed to testify as to what satisfies a specific legal standard or what a particular statute or regulation means. However, of course, experts may offer opinions “relevant to applying a legal standard” including testimony “describing sound professional standards and identifying departures from them.”

    1. Daniel Billington

    Billington inspected the site of the incident, took various measurements, and reviewed the footage from the night in question, along with an extensive list of documentary evidence and depositions in this case. He concluded, among other things, that DeLeon struck the air station during the incident in question, that the air station was a close-clearance structure, that the yard was too dark, which posed a danger to employees, and that the bent ladder prevented DeLeon from standing upright, contributing to him hitting the air station.

    Billington took detailed and specific measurements at the railyard, including quantifiable lighting measurements under similar weather and time conditions, and he used his experience and measurements to produce a 3D render of the accident to explain how this tragic and perplexing incident occurred.

    The Court found that Billington was qualified to testify on these topics and that his inspection of the site, reliance on his experience, and review of the documents constituted a proper methodology for an accident reconstructionist.

    One argument Norfolk made that requires special attention is that Billington’s accident reconstruction testimony would not be helpful to a jury. The argument centers on the fact that much of his accident reconstruction is based on the video of the incident, which the jury can watch itself.

    This Court has watched the video of the incident several times. It does not speak for itself. The camera was set up far away from the site of the incident. The video is dark, at times blurry, and in black and white.

    2. Colon Fulk

    Fulk reached various conclusions about the safety of the train yard on the night of the incident, the safety rules Norfolk had in place at the time, and the factors that may have contributed to the accident. He testified about how difficult it is for on-the-ground railmen to know exactly how fast a train is going, especially in nighttime conditions, and opined that it was unsafe for Norfolk to have a rule allowing railmen to board moving trains at all. He testified about many other issues as well, including the dangers posed by the defective ladder and insufficient lighting at the railyard. In reaching his conclusions, he relied not only on the documentary evidence in this case but also on his inspection of the site of the incident.

    Norfolk’s main arguments to exclude Fulk’s opinions are that he lacked a reliable methodology and that his opinions are conclusory. However, the Court found that he has employed a proper methodology for an expert in his field and has explained his reasons sufficiently. He reviewed the records relevant to the incident, and inspected the site of the incident, taking specific measurements and photos, and explained the reasons for his findings in an expert report. This is not an area of expertise where, for example, an expert could point to specific mathematical methodology for his opinion. Fulk’s methodology and opinions (that are not legal conclusions, as discussed above) are proper, and are similar to many other cases in which he has been allowed to testify over the years.

    3. Jason Engle

    Engle’s conclusions include that the bent ladder was unsafe, that the railcar with the bent ladder should not have been in service until the ladder was fixed, and that Norfolk had insufficient, and at times even actively dangerous, safety procedures.

    Norfolk’s argument to exclude Engle is a bit shorter and refers to or mirrors the arguments on Fulk, namely that the expert lacks methodology and has conclusory opinions.

    The only notable difference is that they admit that Engle provided some “additional detail” compared to Fulk. Like Fulk’s expert report, Engle’s expert report exhibited that he has relevant, specialized experience and that he employed a reliable methodology.

    Held

    The Court granted in part and denied in part Norfolk’s omnibus motions in limine to exclude the causation opinions of experts Daniel Billington, Colon Fulk, and Jason Engle.

    Key Takeaway

    Indeed, courts often exclude expert testimony analyzing videos when a jury is just as capable of doing the same thing. While Norfolk argued that Billington brought no more to the table on this issue than a layperson who watches the video, a review of Billington’s report tells a different story.

    Billington relied on his extensive experience in accident reconstruction, used video enhancement techniques to view it more closely, employed the study of kinematics in his analysis, did an in-person inspection of the incident site, and produced a 3D model of the incident to help explain what happened. Billington has provided an analysis that goes way beyond a simple recounting of what he believes the video depicts. And to the extent Norfolk is dubious of Billington’s opinions, that’s what cross-examination is for.

    Case Details:

    Case Caption: Deleon V. Norfolk Southern Railway Company
    Docket Number: 2:21cv224
    Court Name: United States District Court, Indiana Northern
    Order Date: May 19, 2026
  • Fire Investigation Expert Was Allowed to Opine on UL Listing

    Fire Investigation Expert Was Allowed to Opine on UL Listing

    On November 10, 2022, Kenneth and Phyllis Zerr perished in a house fire. Plaintiffs—the Zerrs’ children and Kenneth Zerr’s estate—alleged that the fire was caused by a defective dehumidifier produced by Gree.

    To support their theory that the fire was caused by a defective dehumidifier, Plaintiffs planned to use expert witnesses. On the origin of the fire, Plaintiffs offered Robert D. Helmkamp. On potential electrical causes of the fire in the room identified as the origin, Plaintiffs offered William Truss. And on the origin of the fire within the dehumidifier and design defects in the dehumidifier, Plaintiffs offered Derek Starr.

    Together, the experts purported to establish the fire’s cause by identifying the origin of the fire through Helmkamp, eliminating alternative causes through Truss, and examining the dehumidifier to establish an origin theory through Starr. All three experts purported to have relied on the National Fire Protection Association’s publication, NFPA 921: Guide for Fire and Explosion Investigations (“NFPA 921”). However, Defendants filed motions to exclude all three expert witnesses.

    Fire Investigation Expert Witnesses

    Robert David Helmkamp is a Certified Fire Investigator through the International Association of Arson Investigators, the National Association of Fire Investigators, the National Board on Fire Service Professional Qualifications, and the State of Missouri.

    Get the full story on challenges to Robert Helmkamp’s expert opinions and testimony with an in-depth Challenge Study.

    William W. Truss is a Certified Fire and Explosion Investigator (NAFI-CFEI) and a Certified Vehicle Fire Investigator (NAFI-CVFI). He is a member of the Institute of Electrical and Electronics Engineers (IEEE), the International Association of Arson Investigators (IAAI), the National Association of Fire Investigators (NAFI), and the National Fire Protection Association (NFPA).

    He also graduated with Electrical Engineering and Computer Engineering Degrees from the University of Missouri – Columbia in 1987 and is a licensed professional engineer in several states.

    Discover more cases with William Truss as an expert witness by ordering his comprehensive Expert Witness Profile report.

    Derek A. Starr is a professional forensic electrical engineer and fire investigator. Prior to his current employment, he spent more than six years performing certification evaluations at Underwriters Laboratories, Inc.

    Want to know more about the challenges Derek Starr has faced? Get the full details with our Challenge Study report.

    Discussion by the Court

    I. Robert Helmkamp

    To begin with, Helmkamp followed the methods prescribed by NFPA 921 in determining the fire’s origin. He analyzed witness information, fire patterns, and fire dynamics. Helmkamp also performed an inspection of the building, observing fire damage levels and patterns. He examined the exterior of the house before moving to the interior, starting in areas with the least damage and moving to the areas with the most damage. Through his inspection, he determined that the fire started in the utility room by systematically eliminating every other room as a possibility.

    He then used burn patterns and relative fire damage to identify a suspect zone within the utility room. Ultimately, he concluded that “based upon fire patterns, degrees of fire damage, fire behavior indicators and electrical activity within the dehumidifier appliance, it is my professional opinion the fire originated at, or within, the dehumidifier appliance located on the floor in the basement utility room.”

    Defendants also contended that Helmkamp failed to consider evidence of alternative ignition sources, including ceiling-level electrical arcing, minimally damaged combustibles, and the results of the second lab exam. Helmkamp did not ignore such evidence. In his initial report, he noted the “lack of damage observed to combustible and metal components located in close proximity nearby” and “thermal damage, likely masking evidence of electrical arcing.” And in his supplemental report, he considered the “additional investigation and data” collected at the second lab exam, including the opportunity for closer examination of the evidence of ceiling-level electrical arcing. In both reports, he found such evidence consistent with his opinion that the fire originated at or within the dehumidifier. While Defendants’ experts may disagree with Helmkamp about the significance of the evidence, Defendants have not pointed to any “total lack of consideration of .. . clear alternative ignition sources constituting ‘serious error.’”

    II. William Truss

    Defendants argued that Truss’ opinions must be excluded because he failed to follow NFPA 921; he relied on “negative corpus”; he conducted no testing; and he failed to consider alternative ignition sources and contradictory evidence.

    As documented in his initial report, Truss followed NFPA 921’s prescribed method for fire cause determination. His report relied on three site examinations (two of which were joint examinations), a laboratory examination, Helmkamp’s report and several other documents and procedures.

    Truss identified and analyzed electrical artifacts in the area of origin. Truss then systematically eliminated the electrical artifacts other than the dehumidifier as potential causes. He began by eliminating artifacts that were substantially outside the area of origin. Then he eliminated artifacts that showed no evidence of an electrical failure. That left four electrical artifacts that could have been the cause of the fire. Truss then individually evaluated the hypotheses that each of the remaining artifacts contributed to the cause of the fire, explaining why he found that three of them were “inconsistent with the facts and the principles of science.”

    Defendants argued that Truss’ opinion should be excluded because his evaluations of alternative ignition sources lacked “scientific testing, analysis, measurements, calculations, empirical data, or peer-reviewed literature,” but that does not defeat its admissibility.

    However, no specific kind or quantity of “testing” is necessary for Truss’ testimony to qualify as reliable. His evaluations of the four hypotheses cite observations of physical evidence and his own experience.

    Truss addressed “the additional investigation and data collected” in a supplemental report, finding that none of it was in conflict with his earlier opinions.

    III. Derek Starr

    A. Starr’s opinion on the origin of the fire is admissible

    Starr’s opinion was not based only on internal damage to the dehumidifier; he also relied on the opinions of Helmkamp and Truss. Starr also did not ignore the results of the second lab exam. He considered the findings and concluded that they did not support an alternative hypothesis or conflict with his previously stated opinion. Resolving the experts’ disagreements as to the significance of the second lab exam is a job for the jury.

    Therefore, the Court held that Starr’s methods in determining that the fire originated internally to the dehumidifier—relying on observations of physical evidence, scientific principles, experience, and the opinions of Plaintiffs’ other experts—were consistent with NFPA 921. 

    B. Starr’s opinion relating to UL certification is admissible

    Defendants objected to Starr’s opinions relating to the dehumidifier’s UL listing because (1) he ignored the absence of a pattern of dehumidifier fires prior to 2012 and evidence that Plaintiff Hillman purchased the dehumidifier in May 2011, (2) he provided no timeline as to when the UL listing would have been removed and whether it would have actually prevented the sale of the dehumidifier if it was purchased in May 2011, and (3) he did not sufficiently explain UL standards or decision-making processes or “provide any evidence that exceeding a temperature rating under similar testing would automatically trigger removal of the UL Mark.”

    Analysis

    In his initial report, Starr explained what a UL listing is, what purpose it serves, and the requirements UL imposes on manufacturers, including the duty to inform UL if a manufacturer becomes aware that a certified product could pose a “substantial hazard.”

    Starr’s second supplemental report explained why the November 2010 Low Refrigerant Charge Operation Test of a GE-branded dehumidifier is relevant to the dehumidifier at issue in this case; what the test results were; and why they were indicative of a fire hazard. Finally, he opined that the test provided Gree with “knowledge of a substantial hazard to users,” which triggered its duty to notify UL, and would have jeopardized its UL listing.

    Defendants also objected that Starr ignored the evidence that Hillman purchased the dehumidifier in 2011 and “provided no timeline as to when the UL listing would have been removed and/or whether this would have actually prevented the sale of the subject Dehumidifier.”

    But—as far as the Court can tell—Starr’s opinion did not appear to rest on a disputed fact. His opinion did not assert that decertification would have happened on any particular timeline or prevented any particular sale, and it also did not rest on any claims about reports of dehumidifier fires.

    IV. The Experts’ Testimony will not be Excluded under Rule 403

    Defendants also argue that all three experts’ testimony should be excluded under Federal Rule of Evidence 403, because its probative value is substantially outweighed by the danger of confusing or misleading the jury. The Court disagreed. All three experts’ opinions are probative of critical issues the jury will have to decide, and the Court has seen no evidence that they would pose a significant risk of confusing or misleading the jury.

    Held

    The Court denied Defendants’ motions to exclude the testimony of Plaintiffs’ experts Robert Helmkamp, William Truss, and Derek Starr.

    Key Takeaway

    In the context of fire investigations, expert opinions formed on the basis of observations and experience may meet the Rule 702 reliability threshold. Similarly, an expert opinion based on the NFPA 921 investigative guidelines for fire investigations meets this reliability threshold if NFPA 921 is applied reliably.

    Case Details:

    Case Caption: Hillmann V. Gree USA, Inc.
    Docket Number: 4:23cv830
    Court Name: United States District Court, Missouri Eastern
    Order Date: March 16, 2026
  • Pulmonary Medicine Expert’s COPD Opinions Admitted

    Pulmonary Medicine Expert’s COPD Opinions Admitted

    Plaintiff, Edward Montelongo, alleged that he has developed asbestosis due to exposure to asbestos through his work at various facilities, including Avondale Shipyards, Kaiser Aluminum & Chemical Corp., and Shell Oil Company’s Norco and Yscloskey facilities.

    Defendants Huntington Ingalls Incorporated and Shell USA, Inc.’s (collectively, “Defendants”) retained medical expert Dr. Andrew J. Ghio. Plaintiff asked the Court to preclude Ghio from testifying at trial that Plaintiff has chronic obstructive pulmonary disease (“COPD”).

    Pulmonary Medicine Expert Witness

    Andrew Jonathan Ghio is board certified in both internal medicine and pulmonary medicine.

    He is certified by the National Institute for Occupational Safety and Health (“NIOSH”) as a B Reader, meaning that he is certified to interpret radiology and diagnose lung conditions associated with dust exposures, including asbestos. He is widely published in the fields of pulmonary disease and internal medicine.

    Get the full story on challenges to Andrew Ghio ’s expert opinions and testimony with an in-depth Challenge Study.

    Discussion by the Court

    In this case, Plaintiff did not contest that Ghio is qualified to testify as an expert. Rather, Plaintiff challenged the reliability of Ghio’s opinion that Plaintiff has chronic obstructive pulmonary disease (“COPD”), arguing that it is unreliable in light of the uncontested fact that Plaintiff did not meet the American Thoracic Society (“ATS”) and the Global Initiative for Chronic Obstructive Lung Disease (“GOLD”) criteria for a diagnosis of COPD.

    However, as Defendants argued, Ghio bases his expert opinion on multiple substantial sources other than the ATS and GOLD diagnostic criteria. The Court cannot determine that Plaintiff’s failure to satisfy the ATS and GOLD diagnostic criteria operates as a full-stop bar on Defendants’ experts testifying reliably that Plaintiff may have COPD.

    Held

    The Court denied Plaintiff Edward Montelongo’s motion to partially exclude the testimony of medical expert Dr. Andrew Ghio.

    Key Takeaway

    The fact that opposing parties do not agree with the facts relied upon by an expert or his interpretation of those facts does not render his opinions unreliable; challenges related to the basis of an expert’s opinions are thus best suited for cross-examination, not exclusion.

    Case Details:

    Case Caption: Montelongo V. Bayer Cropscience, Inc.
    Docket Number: 2:25cv555
    Court Name: United States District Court for the Eastern District of Louisiana
    Order Date: May 19, 2026
  • Vocational Rehabilitation Expert Not Allowed to Opine on Business Income Loss

    Vocational Rehabilitation Expert Not Allowed to Opine on Business Income Loss

    Plaintiff John Thomas McReynolds, Jr. asserted claims for breach of contract and bad-faith delay arising from Defendant’s handling of a claim for underinsured motorist benefits under a Group Personal Excess Liability Policy issued by Vault.

    Defendant Vault E&S Insurance Company filed a motion to exclude the testimony of Plaintiff’s vocational expert, Allison Shipp Berry.

    Vocational Rehabilitation Expert Witness

    Allison E. Shipp Berry has substantial education and experience in vocational assessment, work-capacity analysis, labor-market access, and earning-capacity evaluation. Her credentials include advanced degrees in rehabilitation counseling and an MBA, as well as certifications in rehabilitation counseling and life-care planning.

    Get the full story on challenges to Allison Shipp Berry ’s expert opinions and testimony with an in-depth Challenge Study.

    Discussion by the Court

    Berry plainly possessed specialized knowledge concerning vocational impairment and diminished earning capacity. The Court rejected Defendant’s broad contention that Berry is wholly unqualified to testify in this case.

    The more difficult question concerned the scope and reliability of the specific opinions she proposed to offer.

    Vocational Impairment and Diminished Earning Capacity

    The Court first addressed Berry’s opinions regarding Plaintiff’s vocational impairment and diminished earning capacity arising from an asserted occupational change following the accident.

    Berry reviewed Plaintiff’s medical records, interviewed Plaintiff regarding his post-accident functional limitations, reviewed certain financial materials, and utilized vocational resources and labor-market tools commonly employed in her field, including occupational classification and wage data.

    She further opined that Plaintiff could no longer perform the interventional pain-management work that allegedly constituted a significant component of his pre-accident practice and instead transitioned into a more sedentary supervisory or medical-director role. Plaintiff himself testified that he could no longer perform interventional pain-management procedures at the same level after the accident and that he pursued the Baptist Hospital arrangement after recognizing he could no longer continue his prior work in the same manner. Berry’s opinions concerning occupational change and diminished work capacity are therefore not untethered abstractions. The Court concluded that Plaintiff has carried his burden under Rule 702.

    Defendant correctly observed that Berry selected particular occupational codes and wage data that may be subject to challenge. The fact that Defendant believed that Berry selected imperfect comparators did not establish that she employed no identifiable methodology at all.

    Defendant also emphasized that Plaintiff continued receiving a $240,000 salary both before and after the accident. But Berry expressly testified that her earning-capacity analysis was not intended as a reconstruction of Plaintiff’s historical W-2 compensation; rather, it was intended to estimate the difference in vocational earning capacity between Plaintiff’s pre-injury work and his post-injury occupational role. Whether that distinction is persuasive is a matter for the jury. The Court cannot conclude that Berry’s testimony on this issue is so disconnected from accepted vocational analysis as to require exclusion.

    Lack of Specialized Training or Experience in Forensic Accounting

    Although Plaintiff attempted to characterize Berry exclusively as a vocational expert offering vocational opinions, the reports themselves demonstrate that Berry went further. In both her 2023 and 2025 reports, Berry analyzed the financial performance of McReynolds Anesthesia, P.A., compared pre- and post-accident income figures, and calculated alleged annual income losses for the practice.

    The Court concluded that Plaintiff has not demonstrated by a preponderance of the evidence that Berry is qualified or that her methodology is sufficiently reliable. Berry is not a CPA, economist, or business-valuation expert.

    Berry’s business-income calculations were based largely upon a comparison of profit-and-loss statements from selected periods before and after the accident. Yet she admittedly did not review tax returns for either Plaintiff or the medical practice, did not verify the underlying financial data, and did not meaningfully analyze alternative economic causes affecting the practice’s revenue.

    Berry’s methodology assumed that any reduction in the practice’s income was attributable to the accident while failing to account for an acknowledged and substantial change in the business model of the practice itself. Rule 702 requires more than a temporal comparison followed by an assumption of causation.

    The Court is likewise persuaded that these opinions present substantial risks of jury confusion under Rule 403.

    Held

    The Court granted in part and denied in part Defendant Vault E&S Insurance Company’s motion to exclude the opinions and testimony of Plaintiff’s vocational expert, Allison Shipp Berry. 

    Key Takeaway

    Berry was not permitted to testify regarding alleged net-income losses suffered by McReynolds Anesthesia, P.A., or to offer opinions calculating business-income damages based upon the practice’s profit-and-loss statements. Those opinions exceed the scope of her demonstrated vocational expertise and are not supported by a sufficiently reliable methodology under Rule 702. Moreover, because the opinions risk conflating Plaintiff’s individual earning-capacity claim with the financial performance of a separate business entity, any limited probative value they may possess is substantially outweighed by the danger of confusing or misleading the jury.

    Case Details:

    Case Caption: McReynolds V. Vault E&S Insurance Company
    Docket Number: 1:24cv173
    Court Name: United States District Court, Mississippi Northern
    Order Date: May 12, 2026
  • Forensic Engineering Expert Not Allowed to Opine on OSHA Violations

    Forensic Engineering Expert Not Allowed to Opine on OSHA Violations

    Olivia Hernandez and her nephew, Hector Ontiveros, Jr., were working at a pillow manufacturing plant owned and operated by Comfort Revolution Manufacturing of Mississippi, LLC, when Olivia was injured by a “molding pillow carousel” manufactured, sold, and installed by Defendant.

    Hector heard a scream while working on the same assembly line as his aunt Olivia’s head was caught in a pinch point at the demolding area after she attempted to remove a pillow that fell from the mold onto the floor. This unfortunately crushed Olivia’s head, but she was eventually removed from the machine. Olivia later succumbed to her injuries at the hospital.

    Defendants designated Dr. Steven R. Arndt as an expert in human factors, requesting that he “assist in the investigation and understanding of the human factors issues associated with the subject incident.” Plaintiffs designated Mark R. Cannon “to perform an analysis and evaluation of the causal factors which allowed Hernandez to become entrapped, and critique and evaluate Cannon’s responsibility as the designer and installer of the production line.”

    Both parties sought to strike and exclude the other party’s expert witness.

    Human Factors Expert Witness 

    Steven Robert Arndt is a human factors scientist with advanced degrees in industrial engineering- human factors specialization (MSIE and PhD) from the University of Wisconsin. Arndt is a consultant with substantial experience in the investigation and prevention of accidents and injuries related to consumer products, warning labels, instructions, training, industrial and occupational settings, and transportation related systems.

    Discover more cases with Steven Arndt as an expert witness by ordering his comprehensive Expert Witness Profile report.

    Forensic Engineering Expert Witness

    Mark Russell Cannon has over 25 years’ experience in forensic engineering and investigates a wide variety of mechanical and safety issues, including workplace injuries involving machinery, machinery failures and consumer product failures.

    Want to know more about the challenges Mark Cannon has faced? Get the full details with our Challenge Study report.

    Discussion by the Court

    Mark R. Cannon

    The Court is of the opinion that Cannon’s testimony and opinions should be excluded because his report relied heavily on an incorrect OSHA standard.

    Cannon used the 42-inch guardrail height requirement found in OSHA 1910.29(b)(1) to show “Cannon violated OSHA regulations when they installed the ~34-inch barrier.” He also cited other organizational codes requiring a 42-inch-high railing which have no bearing on the case sub judice.

    The Court found that this information was irrelevant for this case’s purposes, and while Cannon did not rely solely on this information, it is foundational to his entire expert report. Plaintiffs argued that Cannon “opined and testified that the standard shows the logic behind a 42-inch height as opposed to the 34-inch height utilized by Cannon USA in its design” and “his opinions were not asserting that the design was unsafe or unreasonably dangerous solely because of an alleged violation or failure to comply with the OSHA standard” These arguments are unconvincing because at several instances, Cannon’s report reads, “[Defendant] violated OSHA regulations.”

    Steven R. Arndt

    Defendant claimed that Arndt’s opinions were necessary to combat the mischaracterization of safety codes put forth by Plaintiffs’ expert, Cannon, and that his testimony was essential to refute Plaintiffs’ expert’s erroneous interpretation of code and regulatory requirements. While the Court took issue with this characterization of Arndt’s testimony, it would not upset a party’s reason for proffering an expert witness.

    Therefore, because Cannon was excluded—along with the testimony Defendants specifically claimed they were using Arndt to combat—the Court struck Arndt’s testimony and opinions regarding any rebuttal against Cannon for the purpose of trial. More specifically, the Court struck the “Rebuttal” section of his expert report and any testimonial reference to it. Additionally, the Court did not permit Arndt to testify to conclusions of law or tell the jury what conclusion it should reach in this matter.

    Held

    • The Court granted in part and denied in part Plaintiffs’ Daubert motion to exclude or limit the testimony of Steven Arndt.
    • The Court granted Defendant’s motion seeking to exclude Plaintiffs’ expert Mark Cannon.

    Key Takeaway

    An expert may never render “conclusions of law,” opine “on legal issues,” or “tell the jury what result to reach.”

    Case Details:

    Case Caption: Nolazco V. Cannon USA, Inc.
    Docket Number: 1:24cv12
    Court Name: United States District Court, Mississippi Northern
    Order Date: March 16, 2026
  • Internet Marketing Expert Allowed to Opine on Claimed Damages

    Internet Marketing Expert Allowed to Opine on Claimed Damages

    This case arises out a contractual dispute between Plaintiff Steelray Consulting, LLC (“Steelray”) and Defendant Overstock.com, Inc. (“Overstock”). Steelray alleged that it developed a “web scraping” technology that acts as a search engine for online vehicle sales and that it sold this technology to Overstock at a steep discount as part of a profit-sharing arrangement. Steelray further alleged that the parties built a business, Overstock Cars, around this technology. Plaintiff claimed that Defendant violated the parties’ agreements relating to Overstock Cars and now seeks damages arising out of breach of contract and breach of the implied covenant of good faith and fair dealing.

    Steelray hired Dr. Jonathan Hochman as an expert witness to help support some of its claimed damages. Hochman’s report discusses the value of certain digital marketing rights that Steelray claims were contractually owed, specifically Overstock’s alleged obligations to include Steelray in three marketing emails per month for five years and to include Overstock Cars on a tab on Overstock’s website.

    Overstock argued that Steelray cannot establish these claimed damages because expert testimony is needed to establish the market value of the rights and that Hochman’s opinion should be excluded under Daubert.

    Internet Marketing Expert Witness

    Dr. Jonathan E. Hochman has more than 30 years of experience in online marketing, advertising, search engine optimization (“SEO”) and Internet technology. He has four degrees in computer science from Yale University, demonstrating both foundational knowledge and cutting-edge expertise in digital systems.

    Want to know more about the challenges Jonathan Hochman has faced? Get the full details with our Challenge Study report.

    Discussion by the Court

    On September 2, 2016, the parties entered into a Consulting Agreement and a Statement of Work (“SOW”) Agreement. Section 11(h) of the SOW provides for certain “continuing benefits” to Overstock Cars for five years following a split-off, including “a continued presence on Overstock’s website” and inclusion in Overstock’s customer emails “no less than three times a month.”

    Hochman calculated the “fair market replacement value” of these marketing rights to be $50,298,526.

    In this case, Overstock did not contend that Hochman’s methods were unreliable. Instead, it argued that his testimony is irrelevant because the $50 million figure he calculated did not describe the value of the marketing rights in a way that is legally permissible to calculate damages.

    Analysis

    Overstock described the marketing rights as an “income-producing asset” and argued that loss of such an asset can only be compensated by an award of the market value of the asset at the time of the contractual breach.

    Utah law does not specifically address damages in terms of income-producing assets, but it does incorporate the basic principle that general damages for breach of contract claims “are measured by ‘the market value of the very thing promised, at the time of performance.’” The parties did not dispute Overstock’s assertion that loss of the marketing rights “is properly compensated only by an award of the market value of the asset at the time of the breach.” Instead, they disagreed about whether Hochman’s analysis described the market value.

    Considering the testimony as a whole, Hochman’s determination that the marketing rights mentioned in § 11(h) of the SOW would be bought or sold at a certain value is consistent with a description of market value. This is not nullified by his further statements that Steelray would have to spend the same amount to purchase similar marketing benefits elsewhere.

    Overstock also argued that Hochman’s description of the marketing rights based on the value of likely impressions did not describe market value because Hochman “performs no analysis of how many of those impressions would result in visits to Overstock’s Cars tab, how many of those visits would result in purchases, and how many of those purchases would result in profits.”

    In this case, the Court does not believe that a market value analysis of the marketing rights must necessarily consider prospective profits that could arise from those rights.

    In sum, the Court held that Hochman’s testimony may be found to describe market value and thus would be helpful in describing damages considerations to the jury.

    Held

    The Court denied Defendant’s Daubert motion to partially exclude the testimony of Jonathan Hochman.

    Key Takeaway

    Logically, the price that a business is willing to pay for a marketing presence or for marketing impressions naturally factors in the business’ determination about whether its marketing investment will turn a profit.

    Essentially, if the marketing rights’ market value is based on the impressions and views that they can produce, and if those impressions already have a determinable value on the market, then admissibility does not require an expert to look at the speculative profits that could result from those rights.

    Case Details:

    Case Caption: Steelray Consulting LLC V. Overstock.Com
    Docket Number: 2:23cv530
    Court Name: United States District Court for the District of Utah
    Order Date: May 04, 2026
  • Maritime Expert Allowed to Opine on the Barge’s Condition

    Maritime Expert Allowed to Opine on the Barge’s Condition

    On September 28, 2020, HC&D and Cashman Equipment entered into a purchase and sale agreement for the offshore deck barge JMC 254, a 250-foot by 72-foot by 16-foot welded steel offshore deck barge.

    HC&D alleged that it was induced to purchase the barge and sustained damages as a result of Cashman Equipment’s fraudulent misrepresentations.

    Defendant filed a motion to exclude or limit the expert testimony of one of Plaintiff’s experts, Fred Rodolf.

    Maritime Expert Witness

    Fred Rodolf Jr. has worked in the commercial maritime industry since 1990. He holds a United States Coast Guard 500-Ton Master’s License and a 4,000 Horsepower Engineer’s License.

    His professional experience includes vessel acquisition, brokerage, structural evaluation, interpretation of ultrasonic thickness surveys, coordination with classification societies, and oversight of structural steel renewal projects.

    Get the full story on challenges to Fred Rodolf ’s expert opinions and testimony with an in-depth Challenge Study.

    Discussion by the Court

    Rodolf relied on a repair quote from a Mexican shipyard, ISP, referred to as the “ISP Quote,” which was a prominent and sometimes exclusive source for formulating his opinions on the condition, value, utility, and repair costs of the barge. Defendant sought to exclude Rodolf’s anticipated testimony to the extent that it relied on the third-party repair quote.

    However, the Court was satisfied that the ISP Quote possessed at least the minimal reliability required to form the basis of Rodolf’s expert opinion.

    Held

    The Court denied Defendant’s motion to exclude or limit the expert testimony of Fred Rodolf.

    Key Takeaway

    Experts do not need to independently validate data upon which they rely if reliance on its accuracy is reasonable for experts in that field. Any expert retained to determine the condition and value of a vessel would certainly reasonably rely on a repair quote in forming an opinion on those topics.

    Case Details:

    Case Caption: Hc&D V. Cashman Equipment Corp.
    Docket Number: 1:22cv10224
    Court Name: United States District Court for the District of Massachusetts
    Order Date: May 08, 2026
  • Roofing Expert Witness Allowed to Opine on the Specialty Tile

    Roofing Expert Witness Allowed to Opine on the Specialty Tile

    This is a hail damage case. The Plaintiff, First Evangelical Lutheran Church of Lincoln, Nebraska, alleged that its roof was damaged in a hailstorm. Allegedly, the Defendant, Brotherhood Mutual Insurance Company, wrongfully delayed or denied certain benefits under its insurance policy.

    Basically, the Plaintiff alleged that its clay tiles, aluminum gutters, copper flashing, and other metal components suffered extensive damage, some of which allegedly caused interior leaks.

    The Plaintiff has designated two experts: Toby Duncan, a roofing consultant, and Matthew Y. Merrell, a licensed professional civil engineer. Specifically, the Defendant sought to exclude any opinions from these experts that a hailstorm occurred on the property, that a storm caused the damage, any “site-specific” storm conditions, such as wind speed or hail size, or that the damage is attributable to a specific weather event.

    The Plaintiff, on the other hand, sought to exclude the opinions of Vincent Hobson, the Defendant’s expert witness.

    Roofing Expert Witnesses

    Toby Duncan is a commercial and residential roofing consultant and project manager specializing in clay tile, slate, and copper roofs.

    Discover more cases with Toby Duncan as an expert witness by ordering his comprehensive Expert Witness Profile report.

    Vincent H. Hobson has over fifty years of experience in roofing and tiles. He also provides extensive consulting services to homeowners, architects, roofing contractors, historians and even other consultants in the tile roofing arena. 

    Get the full story on challenges to Vincent Hobson’s expert opinions and testimony with an in-depth Challenge Study.

    Civil Engineering Expert Witness

    Matthew Yates Merrell has developed a diverse engineering background focused on new construction and resolving difficult construction issues.

    Want to know more about the challenges Matthew Merrell has faced? Get the full details with our Challenge Study report.

    Discussion by the Court

    Merrell

    To begin with, Merrell relied on industry-standard impact tests to determine that the damage he observed on the church’s roof was consistent with damage caused by hail measuring 1.5 inches in diameter. He considered a consulting meteorologist’s report that a hailstorm on April 12 passed over the subject property, and that storm produced hail measuring a maximum of 1.5 inches in diameter. He relied on an interview with the church property committee indicating that the church’s roof had been repaired in 2018, and there were no “cracked, chipped, or fractured tiles” following those repairs.

    His expert report concluded that “impact damage consistent with hail strikes was widespread at the church.” It also concluded, “within a reasonable degree of engineering certainty, that the storm on April 12, 2020 damaged the subject property.”

    The Defendant argued that Merrell had no basis to opine about storm conditions on April 12, including whether a hailstorm occurred or the size of the hail. According to the Defendant, engineers may not give opinions about these kinds of “site-specific storm conditions.”

    However, Merrell attested that he regularly relied on data from meteorologists to form opinions about the cause of damage, and such reliance is an industry standard. Merrell’s report considered other causes of damages, and specifically excluded “damage that appeared unrelated to high winds and hail.” Merrell used the data from the meteorologist to support his findings about the damage to the roof, and that such damage is consistent with 1.5-inch hail; based on the record before the Court, that meteorological data is being used to support his conclusions based on his expertise, not supplant them. The Defendant challenged the factual basis and foundation of Merrell’s conclusions, but in this Court’s view, those arguments go to weight and not admissibility.

    Duncan

    The Defendant also sought to exclude Duncan’s opinions involving assumptions that hail of a particular size struck the property. While Duncan cannot give expert testimony that a hailstorm on April 12 caused the damage, he is not precluded from giving lay testimony regarding the same. Duncan was in Lincoln the day of the alleged hailstorm, and he visited the Plaintiff’s church property.

    He may give expert testimony that, through his professional experience, what he saw appeared to be consistent with hail damage. And, based on his personal knowledge of the weather conditions on April 12, he may testify as to his observations of the size or other characteristics of the hail.

    The Court made it clear that neither Merrell nor Duncan may provide expert opinions that hail of a particular size struck the church on April 12, 2020. However, both may provide the reason they believe hail of a certain size struck the building. Merrell relied on a meteorological consultant to confirm his measurements and the physical indication of certain-sized hail. Duncan relied on his measurements and personal experience with the hail to draw similar conclusions.

    Hobson

    Hobson inspected the church roof at the Defendant’s request, and issued a report in August 2022. The Plaintiff argued that Hobson’s opinions are “unsupported conjecture” and should be excluded.

    It’s clear from Hobson’s deposition testimony that he based his opinions on his fifty years of experience in roofing and tiles. That experience is an appropriate foundation upon which to base expert testimony, including the testimony that an HVAC installation process damaged the tile, that the specialty tile may have manufacturing defects, or that the damage was not widespread enough to have been caused by hail. As a result, the Plaintiff’s arguments all go to weight, not admissibility, and the motion to exclude will be denied by the Court.

    Held

    • The Court granted in part the Defendant’s motion to exclude or limit the testimony of Plaintiff’s experts, Toby Duncan and Matthew Merrell.
    • The Court denied the Plaintiff’s motion to exclude the testimony of the Defendant’s expert, Vincent Hobson.

    Key Takeaway

    In exercising its gatekeeping function, the Court must make a preliminary assessment of whether the reasoning or methodology underlying the proposed expert testimony is valid and of whether that reasoning or methodology properly can be applied to the facts in issue, focusing specifically on the methodology and not the conclusions. To that end, expert testimony that is speculative, unsupported by sufficient facts, or contrary to the facts of the case, is inadmissible.

    Case Details:

    Case Caption: First Evangelical Lutheran Church Of Lincoln, Nebraska V. Brotherhood Mutual Insurance Company
    Docket Number: 4:23cv3180
    Court Name: United States District Court, Nebraska
    Order Date: May 15, 2026
  • Dermatology Expert Not Allowed to Opine on Hair Loss

    Dermatology Expert Not Allowed to Opine on Hair Loss

    On January 19, 2023, Plaintiff Tamie Maddox filed her Complaint against Defendant Conopco, Inc. d/b/a Unilever Home & Personal Care USA, alleging that Defendant, a New York corporation with its principal place of business located at 700 Sylvan Avenue, Englewood Cliffs, New Jersey 07632, caused Plaintiff to suffer from hair loss after she used Defendant’s TRESemmé shampoo containing DMDM hydantoin (“DMDM”).  

    Plaintiff alleged that the DMDM preservative used in Defendant’s products including the TRESemmé Keratin Smooth Shampoo is a chemical that releases a carcinogen known as formaldehyde, which has long been associated with causing hair loss, thinning hair, dermatitis, and other adverse scalp reactions, and has been the subject of numerous complaints and various lawsuits.

    According to Plaintiff’s medical expert, dermatologist Dr. Marc J. Serota, “Defendant’s product caused her hair loss due to an allergic reaction to DMDM.” However, Defendant filed a motion to preclude Serota from testifying at trial.

    Dermatology Expert Witness

    Dr. Marc Jonathan Serota is triple board-certified in dermatology, pediatrics, and allergy and immunology. Serota is recognized as a national expert in dermatology and allergy topics. He also frequently lectures across the country and has published numerous articles in his areas of expertise.

    Want to know more about the challenges Marc Serota has faced? Get the full details with our Challenge Study report.

    Discussion by the Court

    To begin with, Defendant argued that Serota formed his opinion without conducting procedures normally performed by dermatologists outside the litigation context. Moreover, Defendant asserted that Serota’s theory in this case lacked scientific support and that he failed to establish that DMDM or other chemicals could have caused the alleged hair loss at the levels of concentration these chemicals are found in Defendant’s products. Defendant noted that Plaintiff has not consulted with a doctor in several years, that she has been uninsured since 1996, and that she has never been tested for an allergy to DMDM. 

    Serota testified that he essentially relied entirely on Plaintiff’s self-report of her symptoms and some photographs of the affected areas on her body to come to his opinion.

    In this case, because Plaintiff effectively lacked any significant medical records or other medical history that could have informed Serota’s opinion as to her specific condition, Serota would have had to perform some physical examination or laboratory tests to credibly determine whether Plaintiff does in fact have an allergy to DMDM.

    He did not do that here, and as a result, the Court cannot credit his testimony and allow him to present his opinions to a jury as those of a properly informed expert.

    Held

    The Court granted Defendant’s Daubert motion to preclude Marc Serota from testifying at trial.

    Key Takeaway

    A physician who evaluates a patient in preparation for litigation should seek more than a patient’s self-report of symptoms or illness. Therefore, the physician should either examine the patient or review the patient’s medical records.

    Case Details:

    Case Caption: Maddox V. Conopco, Inc.
    Docket Number: 2:23cv293
    Court Name: United States District Court for the District of New Jersey
    Order Date: May 12, 2026
  • Security Expert’s Legal Conclusions Excluded

    Security Expert’s Legal Conclusions Excluded

    This case arises from the shooting death of John Fuller, (the “Decedent”), and wounding of DaJohn Foster at the Winbranch Apartment Complex (the “Property”). Plaintiffs assert a premises liability claim based on Defendants’ alleged failure to take adequate steps to protect them from violent crimes committed by third parties not resident at the Property. Defendant Winbranch Complex, LLC owned the Property and Defendant My Management, LLC served as the third-party fee manager for the Property.

    Plaintiffs retained Jennifer C. St. Clair, an economist, to provide expert testimony on the pecuniary and/or monetary value of the Decedent’s life, and Thomas R. Stutler, a “security specialist.”

    Defendants, Winbranch Complex, LLC, and My Management, LLC d/b/a Apartments Near Me (together, the “Defendants”) filed a Daubert motion to exclude Plaintiff’s experts.

    Security Expert Witness

    Thomas R. Stutler, CPP, JD served as leader for security at two corporations, spanning approximately ten years.

    Want to know more about the challenges Thomas Stutler has faced? Get the full details with our Challenge Study report.

    Economics Expert Witness

    Jennifer Coats St. Clair, MA is a self-employed Labor Economist with over nine years of experience calculating litigation damages, specifically focusing on the economic, financial, and business issues arising in legal disputes. She earned a Master of Arts in Economics from the University of Memphis in 2016, where she also achieved All But Dissertation (“ABD”) status after passing doctoral comprehensive examinations.

    She has taught Economics at the University of Memphis and Christian Brothers University. Since 2017, St. Clair has served as a consulting economist or econometrician on over 130 federal and state cases, with a substantial portion of her practice involving the calculation of economic losses in personal tort claims.

    Get the full story on challenges to Jennifer St. Clair’s expert opinions and testimony with an in-depth Challenge Study.

    Discussion by the Court

    I. Thomas R. Stutler, CPP, JD

    After summarizing a version of the events underlying the lawsuit, Stutler’s report announces various legal conclusions, including that “the victims were legally on the property” and that “as tenants and guests on the property the Defendants owed a duty to the victims to provide a reasonable safe environment.”

    He then summarized crime statistics for the surrounding area—apparently in support of his assertion of foreseeability—before listing various failures that, if they occurred, “would be a major security failure.”

    The Court held that Stutler’s report did not satisfy Rule 702 and therefore must be excluded.

    Finally, Stutler offered a few opinions that could—depending on the analysis—be the stuff of expert testimony, including: an assessment of Property’s security posture, ten bullet-pointed recommendations for improving that posture; something that looks vaguely like an opinion on breach (although couched in terms of inactions that would be a “serious security failure”); and opinions on causation. The problem is that these opinions are wholly unexplained—they are assertions more than opinions, with no indication that they are the result of a reliable methodology reliably applied.

    II. Jennifer C. St. Clair, MA

    Plaintiffs retained St. Clair to calculate the present value of the economic losses arising from the shooting death of Decedent.

    St. Clair first assumed that Fuller worked for the entire duration of his life. She calculated this to be 18.17 years based on the Markov Process Model of Labor Force Activity. In that scenario, St. Clair found that the value loss would be $830,828. In the second scenario, she assumed that Fuller worked until the Social Security retirement age of 67. The value loss would be $896,139 in that case.

    It should be noted that Defendants did not point to any unique facts or specific medical history that might render any opinion concerning Decedent’s future earnings or household services wildly misleading if not accounted for. 

    Next, Defendants argued that St. Clair failed to accurately calculate income lost because she relied on national average wages as opposed to Fuller’s actual income. Defendants also noted that they have never received income information from Plaintiffs. St. Clair relied on the American Community Survey to determine income specifically for barbers. Defendants also argued that St. Clair committed the same errors in her household services calculation, pointing to her failure to consider Fuller’s actual contributions to the household. St. Clair relied on expectancy data from The Dollar Value of a Day: 2020 Dollar Valuation.

    The Court held that historical earnings and household services are “relevant” to the earnings calculation but not dispositive. St. Clair’s determination that Fuller would have earned more over the course of his working life than the earning capacity that may have been suggested by his salary “is not unreasonable as a matter of law.”

    St. Clair’s analysis “involved a degree of speculation, as does all analysis of future damages, but not unrealistic speculation.”

    Held

    The Court denied Defendants’ motion regarding Jennifer St. Clair’s expert report and granted Defendants’ motion regarding Thomas Stutler’s report.

    Key Takeaway

    Stutler purports to rest his opinion on his “knowledge, training, skill, and expertise,” but even experts who base their opinion on honed expertise must explain how they applied their methodology in the case at hand to arrive at their opinions. Experts must show their work, and if they do not, their opinions must be excluded. The Court’s gatekeeping function under Daubert requires more than simply taking the expert’s word for their testimony.

    Case Details:

    Case Caption: Foster V. Winbranch Complex LLC
    Docket Number: 2:24cv2433
    Court Name: United States District Court, Tennessee Western
    Order Date: May 15, 2026