Expert Witness Profiler

Tag: Gap

  • Law Enforcement Expert Allowed to Opine on the Reactionary Gap 

    Law Enforcement Expert Allowed to Opine on the Reactionary Gap 

    This suit involves the unnecessary use of excessive force by police officers against a black man suffering from a mental health crisis.

    On November 21, 2021, during a mental health crisis, Jabari Asante-Chioke encountered Louisiana State Police (“LSP”) Officer Nicholas Dowdle and East Jefferson Levee District (“EJLD”) Officers Jonathon Downing and Gerard Duplessis (collectively referred to herein as “Officer Defendants”

    Plaintiff, Malikah Asante-Chioke, individually, and on behalf of her father, Jabari Asante-Chioke, herein filed this action against the Defendants, accusing them of failure to use less-than-lethal methods in accordance with training and state and federal law, to subdue Mr. Asante-Chioke.

    Malikah Asante-Chioke filed a motion to exclude the testimony of John J. Ryan.

    Law Enforcement Expert Witness

    John J. Ryan has been actively involved in police practices and law enforcement since 1981.

    He was an active police officer for twenty years in Providence, Rhode Island. In the final year of his active career and since his retirement in June of 2002 from police services, he has been involved in police and law enforcement practices as a private consultant regarding law enforcement issues.

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

    Discussion by the Court

    I. Legal Conclusions

    Plaintiff sought to exclude Ryan’s statement in his report which provides, “It is well known that [if] [sic] an officer reasonably perceives an immediate threat of serious bodily harm or death against themselves, another officer, or any third party, the officer may respond with deadly force.”

    EJLD Defendants argued that a full reading of Ryan’s opinion will explain how this statement is based on Ryan’s “expertise in generally accepted [police] policies, practices, training, and industry standards.”

    While that may be the case, the Court held that Ryan’s statement is not couched in the appropriate terms.

    The Court will not exclude Ryan’s statements of applicable police standards and practices, nor his conclusion that Officers Downing and Duplessis complied with those standards. As the Court has explained, an expert may opine on whether officers complied with applicable police policies and procedures.

    EJLD Defendants argued that Ryan did not need to discuss relevant East Jefferson Levee District policies and procedures and the Court agreed.

    Lastly, Plaintiff argued that Ryan offered impermissible legal opinions because he opined that the EJLD Defendants acted reasonably. While reasonableness is an inadmissible legal conclusion, Plaintiff failed to offer specific examples from Ryan’s report where he opined on the reasonableness of the EJLD Defendants’ actions.

    II. The “Reactionary Gap”

    Plaintiff also argued that Ryan is unqualified to opine on the “reactionary gap” between when an officer receives a stimulus to stop or start firing and when an officer responds to said stimulus.

    EJLD Defendants argued that Ryan is qualified to opine on reaction time because he has spent numerous hours training officers in shooting scenarios, including conducting stimulus drills on a shooting range. The Court agreed with EJLD Defendants.

    Plaintiff also argued that, even if Ryan were qualified, his opinions on the reactionary gap will not help the factfinder because perception reaction times are common sense. However, the Court disagreed. In this case, Ryan may help the factfinder determine whether the Defendants officers’ actions to continue shooting Asante-Chioke were reasonable. Consequently, the Court refused to exclude Ryan’s testimony as unhelpful.

    III. Ryan’s Factual Interpretations

    Plaintiff also argued that the Court should exclude “Ryan’s opinions that merely recite defense counsel’s factual and legal narratives.”

    EJLD Defendants argued that Ryan’s opinions are not based on defense counsel’s factual and legal narratives, but instead are based on his view of the body cam, dash cam, and bystander video evidence. This Court agreed with EJLD Defendants. Throughout his report, Ryan utilized the available video evidence and deposition testimony to formulate his opinions. 

    Held

    The Court granted in part and denied in part Malikah Asante-Chioke’s motion to exclude the testimony of John J. Ryan.

    Key Takeaway:

    While a lay person may have a general understanding of perception reaction times, “a lay person typically would not have experience or knowledge about the time it takes an officer to react to a perceived threat or the absence of a perceived threat.”

    By opining that shooting officers take time to react to a stimulus to stop shooting, Ryan may help the factfinder determine whether the Defendants officers’ actions to continue shooting Asante-Chioke were reasonable.

    Please refer to the blog previously published about this case:

    Biomechanics Expert Was Allowed to Opine on the Source of Bullet Wounds

    Case Details:

    Case Caption: Asante-Chioke V. Dowdle Et Al
    Docket Number: 2:22cv4587
    Court Name: United States District Court, Louisiana Eastern
    Order Date: November 21, 2025
  • Aviation Safety Expert’s Opinion on Organizational Culture Excluded

    Aviation Safety Expert’s Opinion on Organizational Culture Excluded

    This case stemmed from an incident that occurred at Oslo Gardermoen Airport on August 23, 2019. Plaintiff Susan Hardy had flown with United Airlines from New Orleans to New Jersey. From there, she boarded a connecting flight to Oslo, Norway, operated by Defendant Scandinavian Airlines System. According to her claims, she fell while disembarking in Oslo due to a five-to-six-inch gap between the aircraft door and the passenger boarding bridge (PBB), which caused her to suffer injuries.

    Plaintiff engaged expert Matthew G. Robinson, as an “aviation safety expert, accident investigator and reconstructionist.”

    Robinson was asked “to determine the causes of injury to” Plaintiff. He reached four conclusions: (1) The Defendant “violated requirements to ensure” the vertical gap between the aircraft’s floor and the PBB was equal to the lower lip of the aircraft doorsill, providing a level boarding surface; (2) The Defendant “violated International requirements to report” and investigate Plaintiff’s injury; (3) The Defendant’s “failure to warn passengers of the” gap between the aircraft floor and the PBB “led to” Plaintiff’s injury; and (4) The Defendant’s failure to conduct a safety investigation is clear evidence of “a pathological and/or bureaucratic organizational culture.

    Scandinavian Airlines System filed a motion in limine to limit or exclude the testimony of Robinson.

    Aviation Safety Expert Witness

    Matthew G. Robinson, ATP, CFI-I has been the President of the Southern California Safety Institute (“SCSI”) since 2013. Robinson teaches courses in Witness Interviews, Photo-documentation, ICAO requirements, and Evidence Collection and Preservation among others. His work at SCSI also includes instruction on Safety Management Systems and Human Factors.

    Since 2008, Robinson has also conducted technical investigations and provided analysis, reports and testimony in the litigation arena for Robson Forensic, Inc. and now for his own company, Flight Forensics.

    Robinson is a Certified Human Factors Analysis and Classification Professional. He also has a master’s degree in aviation systems safety from Embry-Riddle Aeronautical University.

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

    Discussion by the Court

    Defendant did not contest Robinson’s qualifications as an aviation safety expert; he clearly is an expert and will be allowed to testify in this area. Instead, Defendant filed a motion to exclude his first and third opinions because they are based on unreliable methodologies. Defendant also argued that Robinson’s fourth opinion should be excluded because (1) the opinion did not follow a reliable methodology, (2) there was an analytical gap between the opinion and its basis, and (3) the opinion was unduly prejudicial.

    Robinson May Not Offer his First Opinion that Defendant Violated a “Requirement” that a Level Boarding Surface be Provided

    Defendant moved to exclude Robinson’s opinion that Defendant “violated requirements to ensure the vertical gap between the aircraft cabin floor and [PBB] was equal to the lower lip of the aircraft doorsill.”

    Defendant argued that “too great an analytical gap exists between Robinson’s opinions and the underlying facts” because Robinson based his opinion on the Federal Aviation Administration’s (“FAA”) Advisory Circular No. 150/5220-21C (the “FAA Advisory Circular”). Defendant challenged Plaintiff’s reliance on this document, emphasizing that it held no legal authority in Oslo.

    In response, Plaintiff acknowledged that “the FAA Advisory Circular is not binding on [Defendant] under European law.” Nevertheless, Plaintiff maintained that the FAA Advisory Circular “is an internationally recognized best practice and technical benchmark.” In a supplement to his expert report, Robinson himself conceded that the FAA Advisory Circular is “advisory,” “informational,” and “not regulatory.”

    Given that the FAA Advisory Circular is not binding under European law and is expressly “advisory/informational” and “not regulatory,” the Court ruled that Robinson could not testify that Defendant violated a “requirement” prohibiting a vertical gap between the aircraft door and the PBB. However, the Court also held that Robinson’s opinion on the matter was not entirely unreliable. He was permitted to testify, based on his expertise, about the types and functioning of PBBs, the best practices concerning the height of a PBB relative to aircraft doors, whether Defendant’s actions aligned with those best practices, and the measured distance of the vertical gap on the flight in question.

    In short, the Court concluded that Robinson’s opinion regarding the gap should be challenged through cross-examination, the introduction of opposing evidence, and clear jury instructions on the burden of proof—not through a Daubert motion.

    Robinson May Offer his Third Opinion on the Cause of Plaintiff’s Injuries

    The Defendant moved to exclude Robinson’s opinion that Plaintiff’s fall resulted from (1) the height difference between the aircraft door and the PBB, and (2) Defendant’s failure to warn Plaintiff of this height difference.

    The Defendant sought to exclude Robinson’s causation opinions, arguing that he improperly relied on an unsworn interview with the Plaintiff rather than her later, contradictory sworn deposition testimony. During the March 10, 2025 interview, the Plaintiff told Robinson that the flight crew failed to warn passengers about the gap between the aircraft door and the passenger boarding bridge (PBB), and she also described how the accident occurred. Robinson’s expert report, dated March 13, 2025, reflected this account.

    However, during her deposition on April 17, 2025—about a month later—the Plaintiff testified that she could not recall whether the crew issued any warning or how she had fallen.

    The Defendant contended that Robinson’s decision to credit unsworn testimony over sworn testimony “improperly infringes on the role of the trier of fact.” Despite this, the Court ruled that Robinson’s opinion was not rendered unreliable merely because it partially relied on his interview with the Plaintiff.

    Whether Robinson relied upon adequate information goes to the weight to be assigned to his testimony, as it involved the bases and sources upon which he relied in reaching his conclusions in this case. The difference between Plaintiff’s recall during Robinson’s interview and during her deposition “may be attacked on cross-examination, but the Court cannot say that the [reliance on Plaintiff’s interview] reached the level of ‘altered facts and speculation’ designed to bolster Plaintiff’s position.”

    Robinson May Not Offer his Fourth Opinion on Defendant’s Organizational Culture

    The Defendant moved to exclude Robinson’s fourth opinion that “Defendant’s failure to conduct a safety Investigation and provide safety recommendations is clear evidence of a pathological and/or bureaucratic organizational culture.”

    Quoting the Handbook of Aviation Human Factors (the “Handbook”), Robinson included in his report the statement that pathological organizations handle anomalies or problems through suppression, which “does not make the problem go away.”

    Despite Robinson’s education, work experience, and certification as an HFACS Professional, the Court found his qualifications insufficient to support an expert opinion on the Defendant’s organizational safety culture. His formal training in this area amounted to, at most, twenty-four hours over three days.

    The Court noted that Robinson relied solely on three points to support his opinion: the Defendant’s failure to investigate the Plaintiff’s incident, its failure to address the gap between the aircraft door and the PBB, and the Handbook in support of his organizational safety culture opinion. As a result, the Court concluded that even if Robinson were qualified to testify on organizational safety culture, his opinion in this case lacked reliability.

    During his deposition, Robinson failed to identify specific evidence backing his conclusions. He did not refer to any materials reflecting the Defendant’s actual operations, corporate culture, or established patterns and practices. Ultimately, his opinion appeared to rest entirely on his interpretation of the Handbook and the absence of a post-incident investigation.

    To add to that, the Court held that the probative value of Robinson’s opinion that Defendant’s corporate culture caused the Plaintiff’s injuries is substantially outweighed by the danger of unfair prejudice against Defendant, confusing the issues, misleading the jury, and wasting time.

    Held

    The Court granted in part and denied in part the Defendant Scandinavian Airlines System’s motion in limine to limit or exclude the testimony of Matthew G. Robinson.

    Key Takeaways:

    • The number of sources on which an expert may reasonably rely is virtually infinite and such sources include interviews and general knowledge or experience.
    • Cross-examination, presentation of contrary evidence, and careful instruction on the burden of proof is the proper means of attacking Robinson’s opinion regarding the gap between the aircraft floor and the PBB, not a Daubert motion.

    Case Details:

    Case Caption: Hardy V. Scandinavian Airlines System
    Docket Number: 2:21cv1591
    Court Name: United States District Court, Louisiana Eastern
    Order Date: June 23, 2025
  • Electrical Engineering Expert’s Testimony Addressing the Coverage Gap Admitted

    Electrical Engineering Expert’s Testimony Addressing the Coverage Gap Admitted

    Puerto Rico Telephone Company (“Plaintiff” or “Claro”) brought this suit against the Municipality of Aguada, Hon. Christian Cortés-Feliciano, in his capacity as Mayor of the Municipality of Aguada, and Wesley Vega, in his capacity as Planning Director of the Municipality of Aguada (“Defendants” or “the Municipality”), for alleged violations of Federal Telecommunications Act of 1996 (“TCA”) based on Defendants’ denial of an application to install fiber optic cables and poles in the Municipality of Aguada in Puerto Rico.

    Defendants challenged Plaintiff’s expert report prepared by Engineer Ricardo Matos-Acosta (“Eng. Matos-Acosta”), which they argue did not comport with Federal Rule of Evidence 702.

    Electrical Engineering Expert Witness

    Ricardo Matos-Acosta concentrated his practice in the following areas: electrical engineering, design, optimization, and planning of radio frequency (“RF”) wireless networks for voice, data, video and internet.

    He completed a Master’s in Electrical Engineering at the Polytechnic University of Puerto Rico.

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

    Discussion by the Court

    Initially, the Defendants argued that Eng. Matos-Acosta’s report did not have any citation to “relevant scientific authorities that validate or otherwise support the methodology being employed” in the report, thus alleging a violation of Federal Rule of Evidence 702. Specifically, Matos-Acosta was hired to conduct an analysis of the current wireless service coverage in the Municipality of Aguada around a site that Claro identifies as “AGD1622,” where there is an existing tower.

    Furthermore, the purpose of his report was to identify the existence of a coverage gap and the alternatives to addressing it. In his defense, Matos-Acosta stated in his sworn affidavit accompanying the report that he utilized his twenty-nine years of experience in electrical engineering, design, optimization, and planning of radio frequency (“RF”) wireless networks, in particular, his work experience in wireless systems for Claro since 1995, in preparing said report.

    Analysis

    To begin with, Eng. Matos-Acosta collected data from Claro’s Element and Network Management Server (the “ENM Server”) during a one-week period in October of 2023 to assess the RF wireless coverage and user experience in Aguada’s Río Grande sector. Moreover, Eng. Matos-Acosta explains each industry term used or relied on in his report. Finally, he provided numerous maps which demonstrated that signal levels in the subject area failed to meet Claro’s service-level standards, thereby supporting his opinion that said levels are insufficient to serve their customers in the area.

    Upon review, a reading of his report makes clear that he gathered data, conducted various tests, and evaluated the findings using his experience in the telecommunications industry to determine whether a coverage gap exists and what options are available to address said gap. In contrast, the Municipality has not provided any testimony or expert opinion to rebut Claro’s showing that a significant gap in coverage exists. Most significantly, the Court held that the Municipality’s Daubert challenge did not point to specific parts of the report that were insufficient or articulate what about Eng. Matos-Acosta’s methodology is not in conformance with widely accepted industry methodologies, practices, and parameters. Instead, it attacks it broadly as unsupported by citations.

    Held

    The Court denied the Defendants’ Daubert motion to exclude Plaintiff’s expert Ricardo Matos-Acosta.

    Key Takeaway:

    Ricardo Matos-Acosta provided numerous maps which demonstrated that signal levels in the subject area failed to meet Claro’s service-level standards to support his opinion that said levels are insufficient to serve their customers in the area. Thus, a reading of his report makes clear that he gathered data, conducted various tests, and evaluated the findings using his experience in the telecommunications industry to determine whether a coverage gap existed and what options were available to address said gap.

    Case Details:

    Case Caption: Puerto Rico Telephone Company V. Municipality Of Aguada Et Al
    Docket Number: 3:22cv1315
    Court Name: United States District Court, Puerto Rico
    Order Date: March 31, 2025
  • Statistics Expert Witness’ Damages Calculation Limited Because She Included Extended Gap Periods in Her Analysis

    Statistics Expert Witness’ Damages Calculation Limited Because She Included Extended Gap Periods in Her Analysis

    Defendant, New Prime, Inc., is a commercial trucking company, and its drivers are required to have a Commercial Driver’s License (“CDL”). It designates its CDL-licensed drivers as A seat, B seat, and C seat. B and C seat drivers are paired with an A seat driver until they attain enough experience to be an A seat driver and are paid less than A seat drivers.

    Separately, Defendant created a program whereby individuals could receive the training necessary to obtain a CDL. This program has been referred to as the Prime Student Driver program, or “PSD program,” and participants have been referred to as “PSDs.” PSDs earn a Commercial Learner’s Permit (“CLP”) as part of that training, and at least some of those with a CLP drive a truck carrying freight for Defendant. Such PSDs are designated “D seat drivers” and must be accompanied by an A seat driver. PSDs are not paid, even when performing duties as a D seat driver.

    Plaintiff, Peter Nyachira, asserted two claims. First, he alleged the failure to pay PSDs (or, perhaps, PSDs when acting as D seat drivers) violates the Fair Labor Standards Act (the “FLSA”) and Missouri’s Minimum Wage Law (the “MMWL”). Second, he asserted the amount paid to B and C seat drivers did not meet the FLSA’s minimum wage requirement.

    One of the factual issues to be resolved is how much time B and C seat drivers worked. This issue is also relevant for PSDs if it is determined they were “employees” under the FLSA and MMWL. Another issue that must be resolved is whether the amount paid to B and C seat drivers satisfied the minimum wage requirements. Plaintiff retained Liesl Fox to testify on these matters.

    Statistics Expert Witness

    Liesl M. Fox is a Senior Consultant and Partner at Quantitative Research Associates, a firm that provides statistical and computing consulting services, where she has been employed since 1997. She has been a statistical consultant for over twenty-five years, including conducting analyses in the fields of litigation and medical research, and has testified as an expert witness.

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

    Discussion by the Court

    Basis for Estimates

    Fox’s estimates of the amount of time B and C seat drivers were working were called into question. To place the issue in context: drivers recorded their time in categories pursuant to the Department of Transportation’s Hours of Service (“HOS”) regulations.

    The Court has already held in one of its previous rulings that the HOS categories did not correspond to time “worked” by drivers, and they therefore could not be relied on for that purpose. The Court further concluded drivers are working regardless of the HOS code that is entered and “this means that drivers engaged in multi-day trips are working 24 hours a day.”

    Defendant argued Fox’s estimates did not sufficiently rely on the HOS logs. However, given the Court’s ruling, there is no basis for concluding Fox’s opinion should be excluded because she did not rely on the HOS logs more than she did.

    Allocation of Time

    Defendant retained its own expert, Dr. Christopher Stanton, Ph.D, to rebut Fox’s opinions and relied on his opinion to fault Fox for “assigning all time corresponding to the full duration of a trip that spans two weekly pay periods to the weekly pay period when the trip ended.”

    It claimed this approach artificially inflates the number of hours worked in the second of the two weeks, creating a false impression that insufficient wages were paid for that week.

    Plaintiff defended Fox’s approach by contending, essentially, that (1) Defendant’s records did not permit a different calculation method that is superior to the one she employed and (2) there is no artificial inflation of damages because Defendant pays drivers a set base amount each week.

    The Court concluded that the dispute between Stanton and Fox did not affect the admissibility of Fox’s opinion. Defendant was free to cross-examine her on the issue, as well as present Stanton’s alternative calculation for the jury’s consideration.

    Starting Point for Calculations

    A collective action was certified under the FLSA for those claims, and a class was certified under Federal Rule of Civil Procedure 23 for the PSDs to assert an Missouri’s Minimum Wage Law claim.

    The class definition for the collective action includes B, C, and D seat drivers who engaged in over-the-road training or team driving since May 9, 2020. The starting point for the Rule 23 class is also May 9, 2020. However, Fox calculated damages for the FLSA claims and the MMWL claims beginning on April 13, 2020, and May 3, 2020, respectively. Plaintiff defended this approach for the FLSA claims by arguing that if Defendant’s violation of the FLSA is willful, the statute of limitations is three years. He provides no explanation for the MMWL claim.

    Defendant insists that the measure of damages is confined to the period described in the class definition. Neither party discusses the issue sufficiently to permit the Court to rule, so the Court defers ruling. Evidence of damages from before May 9, 2020, will not be permitted until the matter is resolved.

    “Blank” Codes for D Seat Drivers

    In addition to requiring drivers to record HOS time entries, Defendant maintained a calendaring system. Drivers are assigned various codes; for instance, “D” indicates they are under dispatch, and “A” indicates they are available for dispatch. In some instances, the calendaring system contains gaps; that is, there is not a code for every moment of every day. Fox defined an “Extended Gap Period” as one lasting 24 hours or more.

    For B and C seat drivers, Fox compared the time covered by Extended Gap Periods to Defendant’s Duty Status Records; if the Duty Status Records indicated the B or C seat driver was working, Fox counted the Extended Gap Period as time for which compensation was due.

    Fox treated PSDs differently. She compared the Extended Gap Period to the Duty Status record; then, if the Extended Gap Period ‘was associated with a calendar code . . . or had no calendar code, the gap remained in the analyses.’ Thus, even when confirming information was absent, Fox’s calculations assumed PSDs were working, despite neither the calendaring system nor the Duty Status records reflecting this. The Defendant argued there is no basis in the record for this assumption.

    The Record establishes the calendaring system was not used for PSDs. Moreover, in her deposition, Fox conceded that 99% of the PSDs did not have any calendar codes, but she included the Extended Gap Periods because doing so is consistent with Plaintiff’s theory.

    PSDs were entitled to compensation for the Extended Gap Periods

    Plaintiff did not explain why PSDs were entitled to compensation for the Extended Gap Periods when (1) no available records suggested they were working during that time and (2) Extended Gap Periods were reflected in a calendaring system that is not used for PSDs. The Court concluded Fox had no basis for including Extended Gap Periods in the number of hours PSDs potentially worked, and therefore this component of her analysis must be excluded.

    Orientation Time for Certain B and C Seat Drivers

    Finally, Defendant argued orientation time for certain B and C seat drivers should be excluded. The Court need not consider Defendant’s argument because the Court granted Defendant summary judgment on Plaintiff’s claim regarding orientation. In other words, damage calculations for this aspect of Plaintiff’s claim were irrelevant and will not be admitted at trial.

    Held

    The Court granted in part, denied in part and deferred in part the Defendant’ motion to strike the expert testimony of Dr. Liesl Fox.

    The Court excluded Fox’s opinions regarding (1) Extended Gap Time for D seat drivers and (2) damages incurred by B and C seat drivers related to their attendance at orientation.

    Key Takeaway:

    Based on Stanton’s alternative calculation, the Defendants claimed that Fox’s approach artificially inflates the number of hours worked in the second of the two weeks, creating a false impression that insufficient wages were paid for that week. However, the dispute between Stanton and Fox did not affect the admissibility of Fox’s opinion.

    Fox conceded that 99% of the PSDs did not have any calendar codes, but she included the Extended Gap Periods because doing so is consistent with Plaintiff’s theory. The Court concluded Fox had no basis for including Extended Gap Periods in the number of hours PSDs potentially worked, and therefore this component of her analysis must be excluded.

    Case Details:

    Case Caption: Nyachira V. New Prime, Inc.
    Docket Number: 6:21cv3211
    Court: United States District Court, Missouri Western
    Order Date: September 13, 2024