Expert Witness Blog

In the recent Massachusetts Supreme Judicial Court decision of Mackie v. Rouse-Weir, 2025, the role and legal protections afforded to a Statistics Expert Witness were central to the court’s analysis of expert immunity and the reliability of expert testimony in civil commitment proceedings.

Background and Parties

The Commonwealth of Massachusetts initiated proceedings to civilly commit George Mackie, a prisoner previously convicted of a sexual offense, as a “sexually dangerous person” (SDP) under state law. The statutory process for such a commitment requires the presentation of expert testimony to establish probable cause and the appointment of qualified examiners to determine if the case should proceed to trial. Dr. Katrin Rouse-Weir served as the probable cause expert, while Dr. Robert Joss acted as a qualified examiner. Both experts submitted reports and provided testimony that contributed to Mackie’s initial adjudication as an SDP.

<p>In the recent case of <a href=”https://law.justia.com/cases/new-york/appellate-division-third-department/2025/cv-23-1932.html”>Matter of Johnstown Comrie Assoc., LLC v Assessor for the City of Johnstown, 2025</a>, the New York Supreme Court, Appellate Division, Third Department, addressed the pivotal role of the <a href=”https://www.jurispro.com/category/sales-s-190″>Sales Expert Witness</a> in a complex property tax assessment dispute involving the valuation of a shopping center. This case provides a clear illustration of how courts evaluate expert witness reliability, methodology, and the impact of their testimony on the outcome.</p>

<strong>Background and Parties</strong>

<p>The petitioner, Johnstown Comrie Associates, LLC, challenged the property tax assessment imposed by the City of Johnstown’s Assessor, arguing that the shopping center’s valuation was excessive. Both parties retained expert witnesses specializing in sales comparison and income capitalization approaches to property valuation. The petitioner’s expert presented an income capitalization analysis, while the respondent’s expert relied primarily on a comparable sales methodology.</p>

In the recent case of Matter of Kosmo Family Trust, Surrogate’s Court, Albany County 2024, the pivotal role of a Trusts & Estates Expert Witness was brought to the forefront in a dispute over the validity of amendments to a family trust. This litigation involved allegations of undue influence, questions of testamentary capacity, and the application of New York’s Dead Man’s Statute, all of which required expert analysis and testimony to resolve complex factual and legal issues.

Background and Parties

The Kosmo Family Trust was the subject of a contested proceeding in the Surrogate’s Court of Albany County, New York. Petitioners sought to invalidate the third and second amendments to the trust, alleging that the respondent, who was both a beneficiary and a fiduciary under the trust, exerted undue influence over the decedent. The respondent was named as agent under the decedent’s power of attorney, health care proxy, and as co-trustee under the third amendment, establishing a close fiduciary relationship with the decedent.

In the recent Arizona Supreme Court case of McAlister v. Loeb, 2025, the reliability and admissibility of a Patents Expert Witness testimony played a decisive role in the outcome of a complex patent dispute involving lost profits, licensing agreements, and allegations of professional misconduct.

Background and Parties

Roy McAlister, an inventor specializing in clean fuel technologies, held several patents through his company, McAlister Technologies, L.L.C. (MT). In 2009, MT entered into a licensing agreement with Advanced Green Technologies, L.L.C. (AGT), which subsequently retained the law firm Loeb & Loeb, L.L.P. for patent-related legal services. Disputes arose when McAlister alleged that AGT breached the licensing agreement and that Loeb & Loeb’s actions clouded MT’s patents, causing prospective licensees to withdraw and resulting in substantial lost profits.

In the landmark Arkansas Supreme Court case of Miller Brewing Company v. Ed Roleson, Jr., Inc., 2006, the role of the Franchising Expert Witness was central to the resolution of a high-stakes dispute between a major brewer and its franchisee. This case illustrates the critical importance of expert testimony in complex franchise litigation, particularly regarding damages and industry standards.

Background and Parties

The dispute arose when Miller Brewing Company, a national brewer, was accused by its franchisee, Ed Roleson, Jr., Inc., of refusing to deal with the franchise in a commercially reasonable manner and in good faith, as required by the Arkansas Franchise Practices Act. The franchisee alleged that Miller’s conduct resulted in significant financial harm, including lost profits from a failed acquisition of another distributorship.

In the recent federal case of Mishra et al v. State Farm Fire and Casualty Company, No. 4:2023cv01537 (N.D. Ala. 2025), the court addressed the admissibility of testimony from a Risk Management Expert Witness in the context of a property insurance dispute. This case provides a clear illustration of the rigorous standards courts apply to expert testimony under Federal Rule of Evidence 702 and the Daubert framework, particularly when the expert’s methodology and qualifications are challenged.

Background and Parties

The plaintiffs, the Mishras, filed suit against State Farm Fire and Casualty Company after a retaining wall at their residence collapsed. The Mishras alleged that the loss was covered under their homeowner’s insurance policy, while State Farm denied coverage, contending that the collapse was excluded under the policy’s terms. Central to the dispute was the cause of the wall’s failure and whether it fell within the scope of covered perils.

In the pivotal case of Mohney v. US Hockey, Inc., 300 F. Supp. 2d 556 (N.D. Ohio 2004), the court’s analysis of a Helmets Expert Witness was central to the adjudication of a complex product liability dispute arising from catastrophic injuries sustained during a youth hockey game. The litigation addressed the compatibility and safety of a helmet and mask combination, with expert testimony scrutinized under the Daubert standard for reliability and relevance.

Background and Parties

The plaintiffs, on behalf of Levi Mohney, a minor who suffered severe spinal injuries during a hockey game, brought suit against US Hockey, Inc. and related parties. The core allegation was that a defectively designed helmet and mask, when used together, failed to protect Levi from injury and, in fact, contributed to the mechanism of harm. The defense countered that the equipment met applicable safety standards and that the injuries resulted from the inherent risks of the sport.

In the landmark case of Mosesian v. Pennwalt Corp., 191 Cal. App. 3d 851 (Cal. Ct. App. 1987), the testimony of a Pesticides Expert Witness was central to the resolution of a complex dispute involving alleged crop damage from pesticide application. This case illustrates the critical role of expert analysis in litigation concerning agricultural chemicals and their effects.

Background and Parties

The plaintiff, Charles Mosesian, owned grapevines in Madera, California. In 1979, after applying Kryocide—a fluoride-based pesticide manufactured by Pennwalt Corporation—Mosesian alleged significant crop losses due to what he described as “Kryocide burn.” Mosesian sued Pennwalt and Helena Chemical Company, asserting strict liability, breach of express warranty, and fraud. The defendants denied liability, contending that Kryocide, when used as directed, did not cause the alleged damage.

In the recent case of Niles v. Nature’s Way Pest Control, New York Other Courts 2019, the court addressed critical issues of property damage and pest control efficacy, relying on the specialized knowledge of an Insects & Pests Expert Witness to evaluate the presence and management of carpenter ants in a residential property.

Background and Parties

Plaintiff Jessica Niles initiated a small claims action against Nature’s Way Pest Control, seeking $4,875 in damages. The dispute arose after Niles purchased a home in Saratoga Springs, New York, where a pre-closing inspection revealed visible evidence of carpenter ants and associated structural damage. The inspection report recommended professional treatment for carpenter ant control. Niles subsequently engaged Nature’s Way Pest Control for a further inspection and advice regarding the pest issue.

In the landmark case of Northwest Airlines, Inc. v. CIR, 1978, the Minnesota Supreme Court addressed the complex issue of valuing a commercial airline’s fleet for tax assessment purposes, with pivotal testimony from an Aviation Valuation Expert Witness.

Background and Parties

Northwest Airlines, Inc., a major commercial airline, contested the valuation of its aircraft fleet as determined by the Minnesota Commissioner of Revenue. The dispute centered on whether the commissioner’s assessment accurately reflected the market value of the airline’s property for taxation. The case required the Minnesota Tax Court to weigh competing valuation methodologies and expert opinions, given the inherent difficulty in appraising a diverse and specialized fleet of commercial aircraft.