Expert Witness Profiler

Tag: Coding

  • Medical Coding Expert’s Testimony About the Health Insurance Claims Admitted

    Medical Coding Expert’s Testimony About the Health Insurance Claims Admitted

    Plaintiff Michael Swartzendruber claimed that Defendants United Healthcare Insurance Company and United Healthcare of the Mid-Atlantic, Inc. (collectively “United”), and Defendants Sentara RMH Medical Center and RMH Medical Group, LLC (collectively “Sentara”) overcharged him for hospital services and/or by making misrepresentations about the charges for his blood tests. 

    On each occasion, Swartzendruber’s blood was drawn at a Sentara satellite outpatient location and tested at Sentara’s main hospital location. Sentara billed, and United processed and reimbursed, charges for medical services based on rates associated with the main hospital location as opposed to rates of certain providers operating at the satellites.

    Plaintiff filed a motion to exclude the expert testimony of Defendants’ expert, Kristina Kahan. Kahan was retained to opine on whether or not the health insurance claims at issue in this case were properly billed.

    Medical Coding Expert Witness

    Kristina B. Kahan is a Registered Nurse, Certified Professional Coder, and senior managing director at Ankura Consulting with decades of clinical, compliance, and coding experience in the healthcare industry.

    She holds multiple coding certifications: Certified Professional Coder (“CPC”), Certified Outpatient Coder (“COC”), and Certified Risk Adjustment Coder (“CRC”).

    Fortify your strategy by reviewing a Challenge Study detailing grounds for excluding Kristina Kahan’s expert testimony. 

    Discussion by the Court

    To begin with, Plaintiff challenged the relevancy and helpfulness of Kahan’s opinions, and disputes that Kahan has offered a sufficient basis on which to offer her opinions. 

    a) Basis for Opinions

    In her report, Kahan concluded that Sentara properly submitted claims for the services at issue in this case and that United properly adjudicated the claims it received from Sentara.

    Specifically, Kahan concluded that Sentara appropriately billed the services rendered as originating from Sentara RMH Medical Center because the services were “performed at off-campus locations of RMH Medical Center and the blood testing was performed at RMH Medical Center’s main hospital location” and thus constituted “facility services.”

    Kahan concluded that Sentara properly billed and United properly adjudicated the claims. In making these conclusions, Kahan evaluated Sentara RMH Medical Center’s hospital certification and Medicare Provider Enrollment, Chain, and Ownership System information. As a result, the Court found that Kahan has developed sufficient bases on which to support her opinions.

    b) Relevancy and Helpfulness

    Defendants asserted that Kahan’s report addressed material aspects of the case—whether Sentara appropriately submitted the claims and whether United appropriately adjudicated them.

    However, Plaintiff argued that Kahan’s report is not helpful to the Court because Kahan offered no testimony that is helpful or necessary for the Court to interpret the contract at issue.

    The Court found that the Kahan Report presented relevant and helpful evidence as it served to assist the Court in understanding the healthcare claims submission and adjudication processes, including the relevant regulations governing these processes, such that the Court is better equipped to address the issues in dispute in this case. 

    Held

    The Court denied the Plaintiff’s motion to exclude Defendants’ expert Kristina B. Kahan.

    Key Takeaway:

    Basically, the parties are correct that the Court can read and interpret the contracts at issue, and the Kahan Report does not improperly delve into the world of contract interpretation. Thus, the Court may consider the Kahan Report for its value in understanding the broader environment of the instant case.

    Case Details:

    Case Caption: Swartzendruber V. Sentara RMH Medical Center Et Al
    Docket Number: 5:22cv55
    Court Name: United States District Court, Virginia Western
    Order Date: September 16, 2025
  • Algorithmic Trading Expert’s Opinion is Irrelevant to Establishing Pretext under Title VII

    Algorithmic Trading Expert’s Opinion is Irrelevant to Establishing Pretext under Title VII

    Zongzong (Nicole) Tao has filed a lawsuit against her former employer, Simplex Investments, LLC, alleging discrimination based on gender and race/national origin, in violation of Title VII and the Illinois Human Rights Act. Simplex is a proprietary trading firm that employs algorithmic high frequency trading strategies to make profits from trading futures and equity options. In 2015, Chinese-American trader Nicole Tao joined Simplex Investments, where she was responsible for monitoring trading strategies, including the Spread Auction Trader (SAT).

    Tao claims she experienced a hostile work environment characterized by aggressive behavior from the Head of Trading, Matt Zimmerman, and a pervasive “fraternity-like” atmosphere. Her responsibilities included monitoring trading strategies, notably the Spread Auction Trader (SAT). Simplex asserts that Tao’s termination resulted from her failure to adequately monitor the SAT’s performance.

    Plaintiff retained Zachary Ziliak to review and analyze the processes and procedures for the development and improvement of automated trading strategies, and “Simplex’s claimed basis for terminating [Tao’s] employment.” Ziliak, currently a lawyer, previously worked as a trader and financial engineer.

    Simplex Investments sought to exclude Ziliak’s expert testimony, claiming: he is unqualified to opine about how to properly operate and manage a high-frequency trading firm in the years 2020-2021; his retrospective analysis of the company’s decision to terminate Tao’s employment was irrelevant; his methodology is unreliable; and he has improperly presented his own narrative of the facts of the case under the guise of expert opinion.

    Algorithmic Trading Expert Witness

    Zachary Ziliak, a Rhodes Scholar with six college and graduate degrees enjoyed a successful career in math, finance, and trading before becoming an attorney. He completed graduate work in mathematics at the University of Oxford and obtained a finance and strategy focused MBA from the University of Chicago.

    Ziliak worked as a “quant” at UBS, a leading global investment bank, pricing exotic derivatives and forecasting volatility. He then took over as head trader at Matlock Capital, designing and implementing an automated option-trading system.

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

    Discussion by the Court

    Ziliak reviewed Simplex’s internal documents regarding its trading strategies, including the Spread Auction Trader, and deposition testimony.

    Based on his background and review of the documents, Ziliak ultimately concluded that:

    “The Spread Auction Trader strategy coding error was not Tao’s fault; that the SAT strategy’s operational behavior in the period from August 2020 to January 2021 would have given Tao no cause to discover or diagnose the error given shortcomings in Simplex’s code and control practices; that the SAT strategy error was inadvertently detected by a developer when implementing unrelated functionality requested by Tao; and that Simplex’s claimed estimate of the dollar impact of the SAT error is imprecise and misleading.”

    Ziliak’s Opinion is Not Relevant to Plaintiff’s Discrimination Claims

    Plaintiff must establish a prima facie case of discrimination by showing that (1) she belongs to a protected class; (2) she met her employer’s legitimate expectations; (3) she suffered an adverse employment action; and (4) another similarly situated employee outside of her protected class received better treatment from the employer.

    In Robertson v. Dep’t of Health Servs., 949 F.3d 371, 378 (7th Cir. 2020), the Seventh Circuit explained that “in determining whether the employer’s reason can be characterized as pretextual, we do not evaluate whether the employer’s proffered justification was accurate or even whether it was unfair. Our sole focus is on whether the employer’s stated reason can be characterized as a falsehood rather than an honestly held belief.”

    Plaintiff sought to use Ziliak’s expert testimony to establish that Simplex’s explanation for Tao’s termination—her alleged SAT strategy coding error (among other performance issues)—was a pretext for discrimination. Ziliak’s opinion aimed to demonstrate that the coding error was not attributable to Tao. The Court, however, determined that the central inquiry in a discrimination case is whether Simplex sincerely believed it had a legitimate, non-discriminatory basis for the termination. Ziliak’s opinion, which focused solely on disputing Simplex’s assessment of Tao’s fault, was deemed irrelevant to proving pretext under Title VII and, therefore, was excluded.

    Held

    The Court granted the Defendant’s motion to exclude the opinion of Zachary Ziliak.

    Key Takeaway:

    In determining whether an employer’s stated reason for an adverse employment action is pretextual (a cover-up for discrimination), courts do not assess the accuracy, fairness, or even the reasonableness of the employer’s justification. Instead, the sole focus is on whether the employer’s stated reason is a lie or a falsehood, rather than an honestly held belief, regardless of the correctness or desirability of reasons offered for employment decisions. After all, the Court’s role is not to judge the wisdom of management decisions, but to ascertain whether the employer’s description of its reasons is honest.

    Case Details:

    Case Caption: Nicole Tao v. Simplex Investments LLC
    Docket Number: 1:22cv1463
    Court: United States District Court, Illinois Northern
    Order Date: March 17, 2025
  • Medical Billing Expert Witness’ Opinions on the Reasonable Value of the Bills Admitted

    Medical Billing Expert Witness’ Opinions on the Reasonable Value of the Bills Admitted

    Plaintiff Wendy Marie Henshaw alleged that she slipped and fell on a liquid substance on October 28, 2021, at the Defendant Wal-Mart’s premises.

    Plaintiff filed a motion to strike Defendant’s medical billing and coding expert, Kathleen DePaolo, MSHI, RHIA, CCS. DePaolo, who is a “Certified Coding Specialist,” intended to offer expert testimony regarding the reasonable market value of Plaintiff’s medical bills. DePaolo’s ultimate opinion is that, although Plaintiff’s medical bills amount to $264,324.76, the reasonable value of those bills is $90,053.36.

    Reasonable Value of Plaintiff’s Medical Bills

    DePaolo’s expert report includes item-by-item analyses of Plaintiff’s medical providers’ charges. To calculate the reasonable value of Plaintiff’s medical bills, DePaolo used a “three-pronged analysis.”

    First, DePaolo audited Plaintiff’s medical bills to ensure that each charge was correctly coded and complied with the “applicable medical billing and coding rules, standards, and federal regulations.” If Plaintiff’s providers failed to code an expense (or if she determined that a provider applied an incorrect code), then DePaolo applied the code that she deemed to be appropriate based on her review of Plaintiff’s medical records.

    Second, DePaolo “determined the reasonable marketplace value for the same services within the same community within in the same year.” To calculate the reasonable value of a line-item charge, DePaolo generally relied on three pricing databases: (1) Physicians’ Fee Reference (Yale Wassermann, DMD Medical Publishers, Ltd); (2) Medical Fees (Context4Healthcare Inc. Practice Management Information Corporation); and (3) Find-A-Code.

    DePaolo specifically reviewed the seventy-fifth percentile value for each code across the three databases, and she identified the median value to be the “national usual and customary value.” She then multiplied the “national usual and customary value” by a geographic modifier based on Plaintiff’s providers’ zip codes. DePaolo concluded that the resulting number was the “reasonable value” for each line item.

    Third, DePaolo conducted a market analysis of outpatient service prices in the Orlando area. To identify additional evidence and further validate the results of her audit, DePaolo reviewed published, hospital-specific data listing local outpatient service prices.

    Medical Billing Expert Witness

    Kathleen DePaolo is a medical billing auditor with specialized expertise in inpatient hospitalization billing including DRG, ICD-10 diagnostic code classification and pricing methodologies. Her expertise lies in medical billing, health information, and revenue data analytics.

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

    Discussion by the Court

    The Plaintiff argued that the Court should exclude DePaolo’s testimony regarding the reasonable market value of Plaintiff’s medical bills because: (1) DePaolo’s opinions are unreliable conduits of hearsay upon hearsay; (2) her opinions and methodology cannot be tested; and (3) her opinions will not assist (and pose an unreasonable risk of misleading) the jury.

    DePaolo’s opinions are unreliable conduits of hearsay upon hearsay

    According to the Court, the Plaintiff failed to recognize that (1) Rule 803(17) of the Federal Rules of Evidence states that “[m]arket quotations, lists, directories, or other compilations that are generally relied on by the public or by persons in particular occupations” are not excluded by the hearsay rule and (2) Rule 703 provides that an expert may rely on inadmissible facts or data in forming her opinion if experts in her particular field would reasonably rely on the same evidence.

    The Plaintiff primarily claimed that DePaolo’s reliance on the three pricing databases is insufficient, considering that DePaolo does not know how the pricing databases compile their data. However, DePaolo and other courts have explained that experts in the medical billing industry routinely rely on the three databases that DePaolo used.

    DePaolo’s opinions and methodology cannot be tested

    The Plaintiff specifically argued that DePaolo’s opinions and methodology cannot be tested because DePaolo (1) declined to demonstrate how she queried the pricing databases during her deposition (because she considered the databases to be proprietary) and (2) merely referenced two peer review studies in her Expert Report.

    Although the average person lacks access to the pricing databases that  DePaolo used, another medical billing and coding expert could surely replicate DePaolo’s calculations. Additionally, Defendant included two letters— authored by highly credentialed individuals—reflecting separate studies of DePaolo’s procedures with its Response.

    The Court concluded that the Plaintiff’s argument that DePaolo’s opinions and methodology cannot be tested is meritless.

    DePaolo’s opinions and testimony will not assist the jury

    Despite the Plaintiff’s argument to the contrary, DePaolo’s testimony plainly relates to the reasonable value of Plaintiff’s medical expenses.

    The Court notes that there is a split in this district regarding the admissibility of medical billing and coding experts’ testimony and that it has previously excluded a medical billing and coding expert because “she provided no analysis as to how she reached her opinions and merely state[d] her opinions in a conclusory fashion.”

    However, considering the detailed nature of DePaolo’s Expert Report (as well as the complicated healthcare billing landscape in United States), the Court is satisfied that DePaolo’s testimony and opinions are sufficiently reliable, relevant, and admissible in this case. Therefore, the Plaintiff, once again, failed to show that DePaolo’s opinions and testimony will not assist the jury.

    Held

    The Court denied the Plaintiff’s motion to strike Kathleen DePaolo’s opinions as to reasonable value of the bills.

    Key Takeaway:

    DePaolo submitted a detailed report on the reasonable market value of the Plaintiff’s medical bills. Her reliance on the three pricing databases was deemed sufficient, and her methodology could be tested despite the Plaintiff’s reservations. Given the complicated healthcare billing landscape in the United States, her testimony, which plainly relates to the reasonable value of the Plaintiff’s medical expenses, could assist the jury.

    Case Details:

    Case Caption: Henshaw V. Wal-Mart Stores East, LP
    Docket Number: 6:23cv2388
    Court: United States District Court, Florida Middle
    Order Date: October 21, 2024