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Expert Witness Insights by Area of Expertise
15 min read
Areas of Expertise :
Economics, Economic Damages, Regulatory Compliance, Product Liability, Vocational Rehabilitation
Published Date:
Last Modified Date:
Health economics and regulatory compliance experts help quantify product-related financial losses and evaluate whether testing, labeling, manufacturing, and other conduct aligned with applicable requirements. This article explains how their analyses interact, why unsupported assumptions or misapplied regulations can threaten admissibility under Rule 702, and how attorneys can vet and prepare these experts.
Product liability cases often involve questions of defect, warnings, causation, and damages. The precise issues depend on the claims and governing law. Attorneys may also need expert analysis of the injury’s financial impact and of how the relevant conduct, testing, labeling, or records compare with the requirements that applied to the product.
Counsel may retain professionals with experience in health economics, forensic economics, economic damages, or the product’s regulatory framework. An economic expert may quantify claimed financial losses using supported factual assumptions and the legal framework identified for the assignment. A regulatory expert may analyze applicable technical requirements, company records, documented agency processes, and relevant compliance practices.
Their opinions may depend on medical findings, employment records, testing data, and discovery materials. When several experts rely on the same important assumption, a weakness in that assumption can affect more than one report. Depending on how central the assumption is, the consequence may range from cross-examination to limitation or exclusion of an opinion.
This guide explains what these experts may contribute, how their work fits together, and which problems in methodology and vetting can place their testimony at risk under Federal Rule of Evidence 702.
In litigation, a health economist with relevant case-specific experience may evaluate healthcare spending, utilization, and other economic effects tied to an injury or treatment. The appropriate measure of medical expense may depend on the governing law, including rules concerning billed amounts, amounts paid, write-offs, and the reasonable value of care.
Depending on the issues, a forensic economist, labor economist, vocational expert, or another qualified specialist may contribute to the analysis. A vocational expert may address work capacity and employment options, while an economist may quantify the resulting financial loss.
The expert may review medical expenses, employment and tax records, wage data, and government statistics. The analysis may also rely on medical, life-care, rehabilitation, or vocational information when experts in the economist’s field would reasonably rely on that kind of information. Under Rule 703, that reliance does not automatically make otherwise inadmissible information admissible at trial. Separately, Rule 702 requires the economist’s resulting opinion to rest on sufficient facts or data and to reflect a reliable application of the methodology.
Depending on the governing law and the evidence, claimed economic losses may include:
The governing law determines which categories are recoverable, how they are valued, who may claim them, and what proof is required.
The economist quantifies the claimed losses using supported assumptions and an appropriate methodology. Unless separately qualified, the economist generally relies on appropriately qualified medical professionals for diagnosis, medical causation, prognosis, and future treatment needs. The economist may present alternative calculations based on competing supported assumptions without independently deciding the medical issue.
That distinction is important. A calculation may be mathematically correct but still unreliable if it begins with an unsupported assumption.
For example, an economist may correctly calculate the present value of projected lifetime care. The calculation may be excluded or limited if the proponent cannot show that the need or duration of the care has an adequate evidentiary basis. When the assumption is sufficiently supported but disputed, the disagreement may instead affect weight.
Pain, suffering, and emotional distress are generally treated as noneconomic damages. Economists ordinarily do not assign them a monetary value, subject to the governing law and the scope of the assignment.
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Product liability cases often involve questions of defect, warnings, causation, and damages. The precise issues depend on the claims and governing law. Attorneys may also need expert analysis of the injury’s financial impact and of how the relevant conduct, testing, labeling, or records compare with the requirements that applied to the product.
Counsel may retain professionals with experience in health economics, forensic economics, economic damages, or the product’s regulatory framework. An economic expert may quantify claimed financial losses using supported factual assumptions and the legal framework identified for the assignment. A regulatory expert may analyze applicable technical requirements, company records, documented agency processes, and relevant compliance practices.
Their opinions may depend on medical findings, employment records, testing data, and discovery materials. When several experts rely on the same important assumption, a weakness in that assumption can affect more than one report. Depending on how central the assumption is, the consequence may range from cross-examination to limitation or exclusion of an opinion.
This guide explains what these experts may contribute, how their work fits together, and which problems in methodology and vetting can place their testimony at risk under Federal Rule of Evidence 702.
In litigation, a health economist with relevant case-specific experience may evaluate healthcare spending, utilization, and other economic effects tied to an injury or treatment. The appropriate measure of medical expense may depend on the governing law, including rules concerning billed amounts, amounts paid, write-offs, and the reasonable value of care.
Depending on the issues, a forensic economist, labor economist, vocational expert, or another qualified specialist may contribute to the analysis. A vocational expert may address work capacity and employment options, while an economist may quantify the resulting financial loss.
The expert may review medical expenses, employment and tax records, wage data, and government statistics. The analysis may also rely on medical, life-care, rehabilitation, or vocational information when experts in the economist’s field would reasonably rely on that kind of information. Under Rule 703, that reliance does not automatically make otherwise inadmissible information admissible at trial. Separately, Rule 702 requires the economist’s resulting opinion to rest on sufficient facts or data and to reflect a reliable application of the methodology.
Depending on the governing law and the evidence, claimed economic losses may include:
The governing law determines which categories are recoverable, how they are valued, who may claim them, and what proof is required.
The economist quantifies the claimed losses using supported assumptions and an appropriate methodology. Unless separately qualified, the economist generally relies on appropriately qualified medical professionals for diagnosis, medical causation, prognosis, and future treatment needs. The economist may present alternative calculations based on competing supported assumptions without independently deciding the medical issue.
That distinction is important. A calculation may be mathematically correct but still unreliable if it begins with an unsupported assumption.
For example, an economist may correctly calculate the present value of projected lifetime care. The calculation may be excluded or limited if the proponent cannot show that the need or duration of the care has an adequate evidentiary basis. When the assumption is sufficiently supported but disputed, the disagreement may instead affect weight.
Pain, suffering, and emotional distress are generally treated as noneconomic damages. Economists ordinarily do not assign them a monetary value, subject to the governing law and the scope of the assignment.
The reliability of an economic damages opinion depends on its assumptions, data, methodology, legal framework, and valuation date.
A sound analysis usually requires the economist to:
When personal records are incomplete, the economist may use appropriate occupational, industry, labor-market, geographic, or population data, provided the expert explains why the substitute is a reasonable fit and how its limitations affect the estimate.
The expert should also choose an inflation or price index that reasonably fits the type of expense or loss being projected. A broad consumer-price measure may not accurately reflect changes in medical costs, wages, or prices within a particular industry, so the expert should explain why the selected index fits the loss being projected.
Consider a plaintiff with seasonal work and uneven earnings. A broad national wage estimate may overstate or understate the loss if it does not reflect the worker’s occupation, location, schedule, or employment history.
Common warning signs include promotion assumptions that lack case-specific support, unsupported wage growth, unexplained retirement assumptions, overlapping loss categories, and failure to discount future losses when the governing law requires it.
Depending on their significance, these issues may concern more than arithmetic and may show that the expert did not reliably apply the method to the facts.
A regulatory expert may help identify and analyze the technical requirements, regulatory pathways, and standards relevant to the product during the period at issue. The court determines the governing law and the legal effect of those materials.
The relevant federal agency or agencies depend on the product, use, and regulatory issue:
Depending on the product and claim, the analysis may also consider state requirements, consensus standards, contractual specifications, and industry practices, while recognizing that these sources may have different legal significance. A voluntary standard or industry practice may be relevant evidence, but it does not automatically define the governing legal duty.
Depending on the product, regulatory program, and assignment, the expert’s review may include:
The timing, purpose, admissibility, and legal significance of recalls or later agency communications must be evaluated separately. Their existence does not by itself prove that the product was defective when sold.
One important part of the analysis is distinguishing mandatory regulatory requirements from guidance, recommendations, and other nonbinding materials.
Statutes, regulations, agency guidance, voluntary standards, and company policies may play different roles in the analysis and do not necessarily carry the same legal force. Treating them as interchangeable can weaken the opinion.
FDA guidance documents generally explain the agency’s current views and recommended approaches, but they usually do not create binding obligations for FDA or the public. A mandatory requirement must come from applicable legal authority, such as a statute, regulation, or enforceable agency action, rather than from guidance alone.
An expert who treats every guidance document as binding may overstate what the regulated party was legally required to do.
Regulatory experts may explain technical requirements, documented agency procedures, and how conduct compares with relevant standards. They should avoid unsupported speculation about what an agency would have done in a hypothetical situation. Because the court determines the governing law, an expert should focus on specialized analysis rather than simply assign a legal label to the facts.
Regulatory compliance can matter in product liability litigation, but its effect depends on the product, claim, governing statute, and jurisdiction.
Regulatory compliance may be relevant evidence and, under some statutes, may create a presumption or defense. It does not necessarily resolve every question about defect, warnings, causation, or liability.
The legal effect of an alleged regulatory violation also depends on the governing law and claim. A violation does not automatically create a private right of action, establish negligence per se, prove a defect, or establish causation.
A regulatory analysis should focus on three questions:
Federal preemption may also affect the case. Some federal statutory schemes preempt particular state-law claims, while other claims are not preempted under the governing law.
Regulatory approval, clearance, certification, registration, or compliance does not have the same legal effect under every statutory scheme.
Preemption is highly specific to the product, statutory scheme, regulatory history, and state-law claim.
As Riegel and Wyeth illustrate, preemption depends on the governing federal scheme and the specific state-law duty at issue. In Riegel, the Court held that the Medical Device Amendments preempted state-law claims that would impose safety or effectiveness requirements different from or in addition to the federal requirements governing a premarket-approved device. Claims alleging duties that parallel federal requirements require a separate analysis.
In Wyeth, the Court held that federal law did not preempt the particular failure-to-warn claim involving the prescription drug at issue. The Court explained that the manufacturer could have strengthened the warning through FDA’s “changes being effected” process without first obtaining agency approval, and the record did not establish that FDA would have rejected the change. That result does not establish that every prescription-drug failure-to-warn claim avoids preemption. Other products and claims require their own analysis under the applicable law.
Timing matters as well. Experts should identify the period covered by their analysis and explain when each requirement, standard, study, or other source became available. Experts should distinguish information available during the relevant period from later developments and should explain the limited purpose, if any, for which later information is considered.
In practice, these experts often work from different parts of the same evidentiary record.
A regulatory expert may examine the technical requirements and regulatory materials relevant to the product and how the company responded, based on the available records and evidence. Medical experts may address diagnosis, causation, and prognosis. Engineering, scientific, or human-factors experts may address technical design issues, testing, risk, alternative designs, warning communication, or causation, while the court supplies the governing legal standard for defect. Vocational experts may address work capacity and employment options.
The economist may use relevant findings as disclosed assumptions when economists would reasonably rely on that kind of information and the resulting opinion has a sufficient basis. The economist may then combine those assumptions with employment, financial, and statistical data to quantify claimed losses.
The risk is that one unsupported assumption can spread across several reports.
Each expert should identify the facts reviewed, the outside findings relied upon, the assumptions used, and whether the opinion changes if an important assumption is rejected.
As a practical quality-control step, counsel should compare reports to identify inconsistent facts, timelines, assumptions, or terminology that may require clarification.
For example, a life-care planner may project treatment that the medical record does not adequately support. The permissible foundation for a life-care plan may vary by jurisdiction and by the planner’s qualifications.
An economist may also assume that the plaintiff cannot return to work even though a vocational analysis identifies potentially suitable employment. Counsel and the experts should determine whether the reports use consistent assumptions about work capacity, availability, compensation, and mitigation.
Depending on how central they are to the opinions, these gaps may create Rule 702 concerns or provide material for cross-examination.
Experts may coordinate their work, but each should preserve independent judgment and stay within the limits of the expert’s own qualifications.
A strong résumé does not correct a weak analysis.
Under Federal Rule of Evidence 702, a witness must be qualified through knowledge, skill, experience, training, or education. The proponent must demonstrate to the court, more likely than not, that the expert’s specialized knowledge will help the trier of fact, that the testimony is based on sufficient facts or data, that it is the product of reliable principles and methods, and that the opinion reflects a reliable application of those principles and methods to the facts.
Courts examine both the method and how the expert applied it.
An accepted damages model may still be unreliable if the wage base lacks adequate factual support or does not reasonably fit the person and claim being evaluated. A sound regulatory framework may fail if the expert applies requirements from the wrong product category or time period.
An opinion may be excluded or limited when it depends on a material fact or assumption that lacks adequate support.
Examples include future care without an adequate evidentiary basis, work restrictions unsupported by the record or another qualified source, or earnings based on a promotion assumption that lacks case-specific support.
A regulatory opinion may become unreliable when the expert uses the wrong rule, applies a standard from the wrong period, or treats nonbinding guidance as binding law.
The expert should explain the technical meaning and relevance of each authority and how it was used, while avoiding an instruction on governing law or a conclusory opinion about legal liability.
Even a generally reliable method can be applied poorly.
Problems may arise when experts fail to address material conflicting evidence that bears directly on their method, inputs, or conclusions, select data without explaining why it fits, or repeat counsel’s theory without conducting an independent analysis.
Problems may also arise when experts change methods or inputs after encountering unfavorable facts without a documented, methodologically sound explanation. Revising an analysis is not improper when the change responds to new information, corrects an error, or improves the fit between the method and the assignment.
Experts may also face exclusion when they offer opinions outside their demonstrated expertise. They should apply specialized knowledge to the evidence rather than simply attach a legal label to the facts.
Peer review may be relevant in some scientific cases, but it is not required for every type of expert testimony.
After the court finds an opinion admissible, some remaining disputes may affect its weight and can be tested through cross-examination. But when a central assumption lacks adequate support or the method may not have been reliably applied, the court must decide whether the proponent has satisfied Rule 702. The issue cannot automatically be left to the jury as a matter of weight.
The analysis is opinion-specific. A court may admit some opinions from an expert while excluding or limiting others.
Rule 702 governs expert testimony in federal court. State admissibility rules may differ, so counsel should confirm the standard that applies in the relevant jurisdiction.
A practical vetting process can help counsel identify reliability problems before expert disclosure.
Degrees, licenses, and prior testimony are useful starting points, but they do not answer every question. Counsel should also consider whether the expert’s experience matches the product, methodology, and disputed issues in the case.
For practical purposes, counsel can organize the review into three stages.
Counsel should ask whether the expert has handled similar products, regulatory issues, or damages methodologies.
Prior reports, testimony, publications, disciplinary history, and decisions limiting or excluding the expert’s opinions may provide useful context. Counsel should review the reasons and scope of any prior ruling rather than treating the existence of an exclusion as a complete measure of the expert’s reliability.
Before retention, counsel should ask the expert to explain the likely method, the information still needed, and the limits of the proposed assignment.
Counsel may test the method and assumptions, but the expert should retain control over the expert’s professional analysis and conclusions.
Counsel should ask the expert to identify the basis for each material assumption and whether it comes from the record, another qualified expert, or an accepted data source.
This is also the time to compare timelines, identify conflicts among experts, and test how the opinion changes under different reasonable assumptions.
Counsel may test the report for factual consistency and legal relevance, but the opinions, methodology, and professional judgments must remain the expert’s own.
The report should explain the analysis and basis for the opinion rather than merely state a conclusion, while also satisfying any applicable disclosure requirements.
Before disclosure, counsel should test whether the expert can defend each important assumption without moving beyond the expert’s qualifications.
One useful question is: What is the strongest fact against your opinion?
An expert who can acknowledge contrary evidence and explain its importance often presents a more balanced analysis than one who dismisses every unfavorable fact.
Counsel should also confirm that the report, exhibits, compensation disclosures, prior testimony information, source materials, and reliance materials comply with the applicable procedural rules, scheduling order, and court-specific requirements.
Early review may uncover missing records, unsupported care recommendations, inconsistent timelines, and gaps in regulatory documentation before they become disclosure problems.
What may a health economist evaluate in a product liability case?
A health economist qualified for the particular opinions may be asked to evaluate healthcare spending, utilization, and related economic effects. Depending on the assignment, a forensic economist, vocational expert, or another economic damages specialist may address lost earnings, reduced earning capacity, benefits, and household services.
When should attorneys consider retaining these experts?
As a practical matter, attorneys should consider involving them early enough to help identify technical discovery needs and missing evidence. Waiting until the disclosure deadline may leave too little time to obtain records or address unsupported assumptions.
Can one expert address both regulatory compliance and economic damages?
Possibly, but the expert must be qualified to address each subject and must use a reliable basis and method for each opinion. Because the fields involve different knowledge and methods, separate specialists may be better suited to some assignments.
Can an expert rely on findings from another expert?
An expert may rely on facts, data, or professional findings supplied by another person when experts in the relying expert’s field would reasonably rely on that kind of information. The relying expert must still apply independent specialized judgment, and the resulting opinion must satisfy Rule 702. Rule 703 does not permit an expert to serve merely as a conduit for another witness’s opinion, and it does not automatically make otherwise inadmissible basis information admissible at trial.
Does a disagreement over an assumption always require exclusion?
No. Some disagreements affect the weight of an otherwise admissible opinion and can be tested through cross-examination. Exclusion or limitation becomes more likely when a material assumption lacks sufficient support or causes the opinion to fail Rule 702’s reliable-application requirement.
The reliability of an economic damages opinion depends on its assumptions, data, methodology, legal framework, and valuation date.
A sound analysis usually requires the economist to:
When personal records are incomplete, the economist may use appropriate occupational, industry, labor-market, geographic, or population data, provided the expert explains why the substitute is a reasonable fit and how its limitations affect the estimate.
The expert should also choose an inflation or price index that reasonably fits the type of expense or loss being projected. A broad consumer-price measure may not accurately reflect changes in medical costs, wages, or prices within a particular industry, so the expert should explain why the selected index fits the loss being projected.
Consider a plaintiff with seasonal work and uneven earnings. A broad national wage estimate may overstate or understate the loss if it does not reflect the worker’s occupation, location, schedule, or employment history.
Common warning signs include promotion assumptions that lack case-specific support, unsupported wage growth, unexplained retirement assumptions, overlapping loss categories, and failure to discount future losses when the governing law requires it.
Depending on their significance, these issues may concern more than arithmetic and may show that the expert did not reliably apply the method to the facts.
A regulatory expert may help identify and analyze the technical requirements, regulatory pathways, and standards relevant to the product during the period at issue. The court determines the governing law and the legal effect of those materials.
The relevant federal agency or agencies depend on the product, use, and regulatory issue:
Depending on the product and claim, the analysis may also consider state requirements, consensus standards, contractual specifications, and industry practices, while recognizing that these sources may have different legal significance. A voluntary standard or industry practice may be relevant evidence, but it does not automatically define the governing legal duty.
Depending on the product, regulatory program, and assignment, the expert’s review may include:
The timing, purpose, admissibility, and legal significance of recalls or later agency communications must be evaluated separately. Their existence does not by itself prove that the product was defective when sold.
One important part of the analysis is distinguishing mandatory regulatory requirements from guidance, recommendations, and other nonbinding materials.
Statutes, regulations, agency guidance, voluntary standards, and company policies may play different roles in the analysis and do not necessarily carry the same legal force. Treating them as interchangeable can weaken the opinion.
FDA guidance documents generally explain the agency’s current views and recommended approaches, but they usually do not create binding obligations for FDA or the public. A mandatory requirement must come from applicable legal authority, such as a statute, regulation, or enforceable agency action, rather than from guidance alone.
An expert who treats every guidance document as binding may overstate what the regulated party was legally required to do.
Regulatory experts may explain technical requirements, documented agency procedures, and how conduct compares with relevant standards. They should avoid unsupported speculation about what an agency would have done in a hypothetical situation. Because the court determines the governing law, an expert should focus on specialized analysis rather than simply assign a legal label to the facts.
Regulatory compliance can matter in product liability litigation, but its effect depends on the product, claim, governing statute, and jurisdiction.
Regulatory compliance may be relevant evidence and, under some statutes, may create a presumption or defense. It does not necessarily resolve every question about defect, warnings, causation, or liability.
The legal effect of an alleged regulatory violation also depends on the governing law and claim. A violation does not automatically create a private right of action, establish negligence per se, prove a defect, or establish causation.
A regulatory analysis should focus on three questions:
Federal preemption may also affect the case. Some federal statutory schemes preempt particular state-law claims, while other claims are not preempted under the governing law.
Regulatory approval, clearance, certification, registration, or compliance does not have the same legal effect under every statutory scheme.
Preemption is highly specific to the product, statutory scheme, regulatory history, and state-law claim.
As Riegel and Wyeth illustrate, preemption depends on the governing federal scheme and the specific state-law duty at issue. In Riegel, the Court held that the Medical Device Amendments preempted state-law claims that would impose safety or effectiveness requirements different from or in addition to the federal requirements governing a premarket-approved device. Claims alleging duties that parallel federal requirements require a separate analysis.
In Wyeth, the Court held that federal law did not preempt the particular failure-to-warn claim involving the prescription drug at issue. The Court explained that the manufacturer could have strengthened the warning through FDA’s “changes being effected” process without first obtaining agency approval, and the record did not establish that FDA would have rejected the change. That result does not establish that every prescription-drug failure-to-warn claim avoids preemption. Other products and claims require their own analysis under the applicable law.
Timing matters as well. Experts should identify the period covered by their analysis and explain when each requirement, standard, study, or other source became available. Experts should distinguish information available during the relevant period from later developments and should explain the limited purpose, if any, for which later information is considered.
In practice, these experts often work from different parts of the same evidentiary record.
A regulatory expert may examine the technical requirements and regulatory materials relevant to the product and how the company responded, based on the available records and evidence. Medical experts may address diagnosis, causation, and prognosis. Engineering, scientific, or human-factors experts may address technical design issues, testing, risk, alternative designs, warning communication, or causation, while the court supplies the governing legal standard for defect. Vocational experts may address work capacity and employment options.
The economist may use relevant findings as disclosed assumptions when economists would reasonably rely on that kind of information and the resulting opinion has a sufficient basis. The economist may then combine those assumptions with employment, financial, and statistical data to quantify claimed losses.
The risk is that one unsupported assumption can spread across several reports.
Each expert should identify the facts reviewed, the outside findings relied upon, the assumptions used, and whether the opinion changes if an important assumption is rejected.
As a practical quality-control step, counsel should compare reports to identify inconsistent facts, timelines, assumptions, or terminology that may require clarification.
For example, a life-care planner may project treatment that the medical record does not adequately support. The permissible foundation for a life-care plan may vary by jurisdiction and by the planner’s qualifications.
An economist may also assume that the plaintiff cannot return to work even though a vocational analysis identifies potentially suitable employment. Counsel and the experts should determine whether the reports use consistent assumptions about work capacity, availability, compensation, and mitigation.
Depending on how central they are to the opinions, these gaps may create Rule 702 concerns or provide material for cross-examination.
Experts may coordinate their work, but each should preserve independent judgment and stay within the limits of the expert’s own qualifications.
A strong résumé does not correct a weak analysis.
Under Federal Rule of Evidence 702, a witness must be qualified through knowledge, skill, experience, training, or education. The proponent must demonstrate to the court, more likely than not, that the expert’s specialized knowledge will help the trier of fact, that the testimony is based on sufficient facts or data, that it is the product of reliable principles and methods, and that the opinion reflects a reliable application of those principles and methods to the facts.
Courts examine both the method and how the expert applied it.
An accepted damages model may still be unreliable if the wage base lacks adequate factual support or does not reasonably fit the person and claim being evaluated. A sound regulatory framework may fail if the expert applies requirements from the wrong product category or time period.
An opinion may be excluded or limited when it depends on a material fact or assumption that lacks adequate support.
Examples include future care without an adequate evidentiary basis, work restrictions unsupported by the record or another qualified source, or earnings based on a promotion assumption that lacks case-specific support.
A regulatory opinion may become unreliable when the expert uses the wrong rule, applies a standard from the wrong period, or treats nonbinding guidance as binding law.
The expert should explain the technical meaning and relevance of each authority and how it was used, while avoiding an instruction on governing law or a conclusory opinion about legal liability.
Even a generally reliable method can be applied poorly.
Problems may arise when experts fail to address material conflicting evidence that bears directly on their method, inputs, or conclusions, select data without explaining why it fits, or repeat counsel’s theory without conducting an independent analysis.
Problems may also arise when experts change methods or inputs after encountering unfavorable facts without a documented, methodologically sound explanation. Revising an analysis is not improper when the change responds to new information, corrects an error, or improves the fit between the method and the assignment.
Experts may also face exclusion when they offer opinions outside their demonstrated expertise. They should apply specialized knowledge to the evidence rather than simply attach a legal label to the facts.
Peer review may be relevant in some scientific cases, but it is not required for every type of expert testimony.
After the court finds an opinion admissible, some remaining disputes may affect its weight and can be tested through cross-examination. But when a central assumption lacks adequate support or the method may not have been reliably applied, the court must decide whether the proponent has satisfied Rule 702. The issue cannot automatically be left to the jury as a matter of weight.
The analysis is opinion-specific. A court may admit some opinions from an expert while excluding or limiting others.
Rule 702 governs expert testimony in federal court. State admissibility rules may differ, so counsel should confirm the standard that applies in the relevant jurisdiction.
A practical vetting process can help counsel identify reliability problems before expert disclosure.
Degrees, licenses, and prior testimony are useful starting points, but they do not answer every question. Counsel should also consider whether the expert’s experience matches the product, methodology, and disputed issues in the case.
For practical purposes, counsel can organize the review into three stages.
Counsel should ask whether the expert has handled similar products, regulatory issues, or damages methodologies.
Prior reports, testimony, publications, disciplinary history, and decisions limiting or excluding the expert’s opinions may provide useful context. Counsel should review the reasons and scope of any prior ruling rather than treating the existence of an exclusion as a complete measure of the expert’s reliability.
Before retention, counsel should ask the expert to explain the likely method, the information still needed, and the limits of the proposed assignment.
Counsel may test the method and assumptions, but the expert should retain control over the expert’s professional analysis and conclusions.
Counsel should ask the expert to identify the basis for each material assumption and whether it comes from the record, another qualified expert, or an accepted data source.
This is also the time to compare timelines, identify conflicts among experts, and test how the opinion changes under different reasonable assumptions.
Counsel may test the report for factual consistency and legal relevance, but the opinions, methodology, and professional judgments must remain the expert’s own.
The report should explain the analysis and basis for the opinion rather than merely state a conclusion, while also satisfying any applicable disclosure requirements.
Before disclosure, counsel should test whether the expert can defend each important assumption without moving beyond the expert’s qualifications.
One useful question is: What is the strongest fact against your opinion?
An expert who can acknowledge contrary evidence and explain its importance often presents a more balanced analysis than one who dismisses every unfavorable fact.
Counsel should also confirm that the report, exhibits, compensation disclosures, prior testimony information, source materials, and reliance materials comply with the applicable procedural rules, scheduling order, and court-specific requirements.
Early review may uncover missing records, unsupported care recommendations, inconsistent timelines, and gaps in regulatory documentation before they become disclosure problems.
What may a health economist evaluate in a product liability case?
A health economist qualified for the particular opinions may be asked to evaluate healthcare spending, utilization, and related economic effects. Depending on the assignment, a forensic economist, vocational expert, or another economic damages specialist may address lost earnings, reduced earning capacity, benefits, and household services.
When should attorneys consider retaining these experts?
As a practical matter, attorneys should consider involving them early enough to help identify technical discovery needs and missing evidence. Waiting until the disclosure deadline may leave too little time to obtain records or address unsupported assumptions.
Can one expert address both regulatory compliance and economic damages?
Possibly, but the expert must be qualified to address each subject and must use a reliable basis and method for each opinion. Because the fields involve different knowledge and methods, separate specialists may be better suited to some assignments.
Can an expert rely on findings from another expert?
An expert may rely on facts, data, or professional findings supplied by another person when experts in the relying expert’s field would reasonably rely on that kind of information. The relying expert must still apply independent specialized judgment, and the resulting opinion must satisfy Rule 702. Rule 703 does not permit an expert to serve merely as a conduit for another witness’s opinion, and it does not automatically make otherwise inadmissible basis information admissible at trial.
Does a disagreement over an assumption always require exclusion?
No. Some disagreements affect the weight of an otherwise admissible opinion and can be tested through cross-examination. Exclusion or limitation becomes more likely when a material assumption lacks sufficient support or causes the opinion to fail Rule 702’s reliable-application requirement.
Earning Capacity
Expert Witness Insights by Area of Expertise
Expert Witness Insights by Area of Expertise