Practice Tip: Daubert's 'Fit' Requirement

The Majority View of the 'Fit' Requirement

The Daubert court, in reviewing the requirements of Federal Rule of Evidence 702, concluded that an expert's testimony must assist the trier of fact to understand the evidence or to determine a fact in issue. “This condition goes primarily to relevance.” Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579, 591 (1993). The court further noted that this consideration has been aptly described as one of “fit,” but that “'[f]it' is not always obvious, and scientific validity for one purpose is not necessarily scientific validity for other, unrelated purposes.” Id.

Relying on the Daubert court's brief summary of the “fit” requirement, the majority of federal courts that have engaged in a substantive “fit” analysis have focused on whether the expert's proffered testimony is sufficiently tied to the facts of the case or the issues presented to the trier of fact. See, e.g., Behrend v. Comcast Corp., 655 F.3d 182, 216 (3d Cir. 2011) (“Testimony fits when it is sufficiently tied to the facts of the case that it will aid the jury in resolving a factual dispute. [internal quotation marks omitted.]“); Sherman v. Westinghouse Savannah River Co., 263 Fed. Appx. 357, 368 (4th Cir. 2008) (“Indeed, we agree with the court that there is no fit ' between [the expert's] analysis and the limited issue in this case, [i.e.,] whether or not discriminatory management-initiated job assignments produced a difference in radiation dose for black[] and white[] employees. [internal quotation marks omitted.]“).

An Alternative Approach to A 'Fit' Analysis

Three circuit courts provide an alternative to this majority trend and hold that Daubert's “fit” requirement is not satisfied when the disconnect between an expert's data and opinions is too “wide.” The Fifth Circuit applied this analysis in Moore v. Ashland Chemical, 151 F.3d 269, 279 (5th Cir. 1998) and more recently in Chan v. Coggins, 294 Fed. Appx. 934, 938 (5th Cir. 2008). In Chan, defendant Roger Coggins was operating an 18-wheel tractor trailer owned by defendant Boyd Brothers; he struck and killed a pedestrian who had approached the cab of the tractor-trailer to ask Coggins for money. The administratrix of the decedent's estate initiated a wrongful death action and retained an accident reconstruction expert to testify as to how the decedent could have been struck by the tractor-trailer without moving himself in front of the vehicle. The expert sought to prove his theory through the concept of “off-tracking,” which refers to the extent to which the rear wheels of a truck deviate from the path of the front wheels while turning. The expert reviewed the depositions of other witnesses, the Mississippi Uniform Accident Report for the incident, and photographs related to the case to reach his conclusions. He did not have access to the tractor-trailer Coggins drove in the accident, and he did not conduct any tests to reconstruct the events of the accident. The defendants successfully moved to strike the expert's testimony and the court subsequently granted summary judgment in their favor.

In reviewing the district court's decision to preclude the plaintiff's expert from testifying, the Fifth Circuit noted that it is the district court's duty to find that expert testimony is both relevant and reliable before it will be admitted. Specifically, the court noted that in “[e]valuating the reliability of proffered expert testimony, the district court looks beyond credentials and makes sure that there is an adequate 'fit' between data and opinion.” Id. at 937. The Fifth Circuit then concluded that the expert's “credentials, previous testimony in a distinguishable case, and [plaintiff's] citation of one Pennsylvania case allowing expert testimony regarding off-tracking do not persuade us that it was an abuse of discretion for the trial court to determine that his expert opinion in this case was not reliable. 'A court may conclude that there is simply too great an analytical gap between the data and the opinion proffered.'” Id. The court further concluded that “[t]he fact that off-tracking has been discussed in other cases is not persuasive on the issue of whether ' the district court's ultimate conclusion that [the expert's] discussion of off-tracking did not provide a sufficient scientific basis for his opinion.” Id. at 938.

The Fifth Circuit also responded to the plaintiff's argument that her expert should have been allowed to testify because the concept of “off-tracking” was relevant to the facts of the case by noting that “[e]ven if the concept is relevant, it does not necessarily follow that [the expert's] application of the concept to the facts of the case is a proper 'fit.' '[N]othing in either Daubert or the Federal Rules of Evidence requires a district court to admit opinion evidence that is connected to existing data only by the ipse dixit of the expert.'” Id. at 938-39.

United States v. Mamah

In United States v. Mamah, 332 F.3d 475, 478 (7th Cir. 2003), the Seventh Circuit reviewed a district court's decision to exclude the testimony of the defendant's two expert witnesses. There, the defendant, a Ghanaian immigrant, was charged with one count of possession with intent to distribute in excess of 100 grams of heroin. At trial, the defendant sought to introduce the testimony of two expert witnesses in support of his claim that the confession he gave to the FBI after his arrest was false. Specifically, he sought to introduce the testimony of a specialist in the culture of Ghana, who would testify that behaviors adopted by Ghanaians in response to living under a military regime could lead them to make false confessions when confronted by law enforcement authorities, and the testimony of a sociologist to explain how certain interrogation techniques can lead innocent suspects to falsely confess.

The defendant appealed the district court's decision to exclude his experts' testimony, claiming that the court improperly disregarded his experts' impressive educational backgrounds and professional accomplishments. The Seventh Circuit noted that “[w]hether or not [the defendant's experts] grounded their work in sound social science principles and methods, the [district] court still needed to satisfy itself that their work yielded facts and data sufficient to support their proposed testimony. As we have observed, 'experts' opinions are worthless without data and reasons.'” Id. at 477-78. The court further concluded that “[t]he problem with the proposed testimony in this case does not lie in the quality of [the research of the defendant's experts]. Rather the problem is the absence of an empirical link between that research and the opinion that [the defendant] likely gave a false confession.” Id. at 478. Therefore, since there were insufficient facts and data to support the proposition that the defendant's cultural background might have induced him to give a false confession or that an individual who is subjected to coercive interrogation tactics on one occasion will give a false confession on a second occasion when he is not subjected to coercive interrogation tactics, the court concluded the expert's testimony was property excluded.

Samaan v. St. Joseph Hospital

The First Circuit recently joined the Fifth and Seventh Circuits' rigorous approach to Daubert's “fit” requirement in Samaan v. St. Joseph Hospital, No. 11-1480, 2012 U.S. App. LEXIS 386 (1st Cir. Jan.9, 2012). The Samaan court's focus differed slightly from that of the Chan and Mamah courts because the Samaan court was not concerned with the existence of a factual basis for the proffered expert's opinion, but rather the expert's interpretation and application of relevant statistical data from scientifically reliable sources. Regardless, the court followed the same practice of the Fifth and Seventh Circuits by concentrating on the connection between the proffered expert's opinion and the underlying data.

There, the plaintiff was brought to the defendant hospital while experiencing what was believed to be an ischemic stroke or transient ischemic attack brought on by the stoppage of blood flow to part of his brain. Doctors at the hospital did not give the plaintiff an intravenous shot of tissue plasminogen activator (“t-PA”), a form of thrombolytic therapy that works by dissolving clots that are occluding arteries. The plaintiff was transferred to another hospital and then a series of rehabilitation centers before going home, but was partially paralyzed and unable to work. The plaintiff subsequently sued the hospital and his attending physician, alleging medical malpractice and negligent infliction of emotional distress due to their failure to administer the t-PA. The district court excluded the testimony of the plaintiff's expert regarding the cause of the plaintiff's injuries, concluding that the expert's statistical calculations were not responsive to the question of whether the failure to administer t-PA more likely than not caused the plaintiff's injuries.

On appeal, the First Circuit noted that “the scope of a Daubert hearing is not limited to an appraisal of an expert's credentials and techniques but also entails an examination of his conclusions to determine whether they flow rationally from the methodology employed.” Id. at *24. In responding to the plaintiff's claim that his expert was well qualified and relied on acceptable science, the court stated that the issue was not with the expert's credentials or the reliability of his methods, but with the analytical gap between his data and opinions.

Statistical Data

The opinions of the plaintiff's expert rested on statistical data from scientifically reliable sources. The expert first used odds ratios, or ratios of the odds of an adverse outcome, between a group of patients who had received t-PA and a placebo group. Some of these ratios ranged higher than 50% and the expert used them to opine that the plaintiff more likely than not would have recovered had he received the drug. The court pointed out the expert's flawed assumption regarding the odds ratios by noting that “[w]hen a person's chances of a better outcome are 50% greater with treatment (relative to the chances of those who were not treated), that is not the same as a person having a greater than 50% chance of experiencing the better outcome with treatment. The latter meets the required standard for causation; the former does not.” Id. at *27-28. The court illustrated this point by noting that “suppose that studies have shown that 10 out of a group of 100 people who do not eat bananas will die of cancer, as compared to 15 out of a group of 100 who do eat bananas. The banana-eating group would have an odds ratio of 1.5 or a 50% greater chance of getting cancer than those who eschew bananas. But this is a far cry from showing that a person who eats bananas is more likely than not to get cancer.” Id. at *28. In other words, the court concluded that although the odds ratios establish that the plaintiff would have had a greater chance of recovering had he received the t-PA, they do not provide support for the proposition that, had he received the drug, there was a greater than 50% chance that he would have recovered.

The expert also relied on absolute efficacy rates, which in some cases exceeded 50%, and asserted that they were sufficient to prove that the plaintiff's injuries were likely caused by the defendants' failure to administer t-PA. Specifically, he “stated that 52.4% of patients receiving t-PA recovered as measured by a particular scale. Based on this percentage, he suggested that had the plaintiff received t-PA, he more likely than not would have avoided stroke-related injuries.” Id. at *31. Again, the court pointed to the flaws in the expert's reasoning. It noted that his conclusion overlooked the 45.2% of people who recovered even without the benefit of t-PA. The court also noted that “[f]or a small number of patients who would not otherwise have recovered, t-PA would offer some advantage, but for the majority of patients whose conditions would not improve on their own, the administration of the drug would make no difference.” Id. at *31. The court ultimately concluded, therefore, that “[t]he methods that [the plaintiff's expert] employed and the data that he presented were simply too distant from the conclusion that he drew, thus negating an adequate fit.” Id. at *32.

Practical Implications

The First, Fifth and Seventh Circuits' approach in the above-referenced cases is significant because the courts specifically examined the connection between an expert's opinion and underlying data in the context of Daubert's “fit” analysis and used the disconnect between the expert's data and opinion as the basis for precluding testimony. Under this minority, a district court will likely give greater scrutiny to a disconnect between an expert's opinion and underlying data than it would under the “fit” analysis performed by the majority of courts. The minority approach, therefore, provides attorneys with a stronger basis for challenging an opposing expert's testimony on the ground that the testimony is not supported by the underlying data. Consequently, even in jurisdictions that have not adopted this alternative approach to Daubert's “fit” requirement, attorneys should look to frame their challenges to expert testimony under the standard applied by the First, Fifth, and Seventh Circuits.

James H. Rotondo, a member of this newsletter's Board of Editors, is co-chair of the Commercial Litigation Department at Day Pitney LLP, in Hartford, CT. He focuses his practice on product liability, tort and insurance litigation. Michael P. Pohorylo is an associate in the firm.

Daubert requires that federal district court judges engage in a two-prong inquiry when addressing the admissibility of expert testimony. The district court must determine that an expert's proffered testimony has both a reliable foundation and an adequate fit. While many courts have addressed in-depth the first prong of this Daubert test, less attention has been paid to the second prong, the “fit” requirement. Among the courts that have engaged in a substantive “fit” analysis, the majority have focused on whether the expert's proffered testimony is sufficiently tied to the facts of the case or the issues presented to the trier of fact. Under this type of analysis, the courts essentially ask the question “is this testimony relevant?”

Three federal circuits discuss an alternative approach to the “fit” analysis and hold that there is an independent significance to the “fit” requirement. Specifically, these circuits hold that the “fit” requirement is satisfied when an expert's opinion is supported by the underlying data and have precluded expert opinions where there was too great an analytical gap between the data and the opinion proffered.

Although other federal courts have previously determined that an analysis of the connection between an expert's data and opinion is proper during a Daubert hearing, few courts have specifically examined this connection in the context of the “fit” requirement. This alternative approach, therefore, provides attorneys with a stronger foundation when seeking to exclude expert testimony by allowing them to challenge the disconnect between an expert's opinion and data in the context of Daubert's “fit” requirement specifically and seek preclusion on this basis alone.

The Majority View of the 'Fit' Requirement

The Daubert court, in reviewing the requirements of Federal Rule of Evidence 702, concluded that an expert's testimony must assist the trier of fact to understand the evidence or to determine a fact in issue. “This condition goes primarily to relevance.” Daubert v. Merrell Dow Pharmaceuticals, Inc. , 509 U.S. 579, 591 (1993). The court further noted that this consideration has been aptly described as one of “fit,” but that “'[f]it' is not always obvious, and scientific validity for one purpose is not necessarily scientific validity for other, unrelated purposes.” Id.

Relying on the Daubert court's brief summary of the “fit” requirement, the majority of federal courts that have engaged in a substantive “fit” analysis have focused on whether the expert's proffered testimony is sufficiently tied to the facts of the case or the issues presented to the trier of fact. See, e.g., Behrend v. Comcast Corp. , 655 F.3d 182, 216 (3d Cir. 2011) (“Testimony fits when it is sufficiently tied to the facts of the case that it will aid the jury in resolving a factual dispute. [internal quotation marks omitted.]“); Sherman v. Westinghouse Savannah River Co. , 263 Fed. Appx. 357, 368 (4th Cir. 2008) (“Indeed, we agree with the court that there is no fit ' between [the expert's] analysis and the limited issue in this case, [ i.e. ,] whether or not discriminatory management-initiated job assignments produced a difference in radiation dose for black[] and white[] employees. [internal quotation marks omitted.]“).

An Alternative Approach to A 'Fit' Analysis

Three circuit courts provide an alternative to this majority trend and hold that Daubert's “fit” requirement is not satisfied when the disconnect between an expert's data and opinions is too “wide.” The Fifth Circuit applied this analysis in Moore v. Ashland Chemical , 151 F.3d 269, 279 (5th Cir. 1998) and more recently in Chan v. Coggins , 294 Fed. Appx. 934, 938 (5th Cir. 2008). In Chan, defendant Roger Coggins was operating an 18-wheel tractor trailer owned by defendant Boyd Brothers; he struck and killed a pedestrian who had approached the cab of the tractor-trailer to ask Coggins for money. The administratrix of the decedent's estate initiated a wrongful death action and retained an accident reconstruction expert to testify as to how the decedent could have been struck by the tractor-trailer without moving himself in front of the vehicle. The expert sought to prove his theory through the concept of “off-tracking,” which refers to the extent to which the rear wheels of a truck deviate from the path of the front wheels while turning. The expert reviewed the depositions of other witnesses, the Mississippi Uniform Accident Report for the incident, and photographs related to the case to reach his conclusions. He did not have access to the tractor-trailer Coggins drove in the accident, and he did not conduct any tests to reconstruct the events of the accident. The defendants successfully moved to strike the expert's testimony and the court subsequently granted summary judgment in their favor.

In reviewing the district court's decision to preclude the plaintiff's expert from testifying, the Fifth Circuit noted that it is the district court's duty to find that expert testimony is both relevant and reliable before it will be admitted. Specifically, the court noted that in “[e]valuating the reliability of proffered expert testimony, the district court looks beyond credentials and makes sure that there is an adequate 'fit' between data and opinion.” Id. at 937. The Fifth Circuit then concluded that the expert's “credentials, previous testimony in a distinguishable case, and [plaintiff's] citation of one Pennsylvania case allowing expert testimony regarding off-tracking do not persuade us that it was an abuse of discretion for the trial court to determine that his expert opinion in this case was not reliable. 'A court may conclude that there is simply too great an analytical gap between the data and the opinion proffered.'” Id. The court further concluded that “[t]he fact that off-tracking has been discussed in other cases is not persuasive on the issue of whether ' the district court's ultimate conclusion that [the expert's] discussion of off-tracking did not provide a sufficient scientific basis for his opinion.” Id. at 938.

The Fifth Circuit also responded to the plaintiff's argument that her expert should have been allowed to testify because the concept of “off-tracking” was relevant to the facts of the case by noting that “[e]ven if the concept is relevant, it does not necessarily follow that [the expert's] application of the concept to the facts of the case is a proper 'fit.' '[N]othing in either Daubert or the Federal Rules of Evidence requires a district court to admit opinion evidence that is connected to existing data only by the ipse dixit of the expert.'” Id. at 938-39.

United States v. Mamah

In United States v. Mamah , 332 F.3d 475, 478 (7th Cir. 2003), the Seventh Circuit reviewed a district court's decision to exclude the testimony of the defendant's two expert witnesses. There, the defendant, a Ghanaian immigrant, was charged with one count of possession with intent to distribute in excess of 100 grams of heroin. At trial, the defendant sought to introduce the testimony of two expert witnesses in support of his claim that the confession he gave to the FBI after his arrest was false. Specifically, he sought to introduce the testimony of a specialist in the culture of Ghana, who would testify that behaviors adopted by Ghanaians in response to living under a military regime could lead them to make false confessions when confronted by law enforcement authorities, and the testimony of a sociologist to explain how certain interrogation techniques can lead innocent suspects to falsely confess.

The defendant appealed the district court's decision to exclude his experts' testimony, claiming that the court improperly disregarded his experts' impressive educational backgrounds and professional accomplishments. The Seventh Circuit noted that “[w]hether or not [the defendant's experts] grounded their work in sound social science principles and methods, the [district] court still needed to satisfy itself that their work yielded facts and data sufficient to support their proposed testimony. As we have observed, 'experts' opinions are worthless without data and reasons.'” Id. at 477-78. The court further concluded that “[t]he problem with the proposed testimony in this case does not lie in the quality of [the research of the defendant's experts]. Rather the problem is the absence of an empirical link between that research and the opinion that [the defendant] likely gave a false confession.” Id. at 478. Therefore, since there were insufficient facts and data to support the proposition that the defendant's cultural background might have induced him to give a false confession or that an individual who is subjected to coercive interrogation tactics on one occasion will give a false confession on a second occasion when he is not subjected to coercive interrogation tactics, the court concluded the expert's testimony was property excluded.

Samaan v. St. Joseph Hospital

The First Circuit recently joined the Fifth and Seventh Circuits' rigorous approach to Daubert's “fit” requirement in Samaan v. St. Joseph Hospital, No. 11-1480, 2012 U.S. App. LEXIS 386 (1st Cir. Jan.9, 2012). The Samaan court's focus differed slightly from that of the Chan and Mamah courts because the Samaan court was not concerned with the existence of a factual basis for the proffered expert's opinion, but rather the expert's interpretation and application of relevant statistical data from scientifically reliable sources. Regardless, the court followed the same practice of the Fifth and Seventh Circuits by concentrating on the connection between the proffered expert's opinion and the underlying data.

There, the plaintiff was brought to the defendant hospital while experiencing what was believed to be an ischemic stroke or transient ischemic attack brought on by the stoppage of blood flow to part of his brain. Doctors at the hospital did not give the plaintiff an intravenous shot of tissue plasminogen activator (“t-PA”), a form of thrombolytic therapy that works by dissolving clots that are occluding arteries. The plaintiff was transferred to another hospital and then a series of rehabilitation centers before going home, but was partially paralyzed and unable to work. The plaintiff subsequently sued the hospital and his attending physician, alleging medical malpractice and negligent infliction of emotional distress due to their failure to administer the t-PA. The district court excluded the testimony of the plaintiff's expert regarding the cause of the plaintiff's injuries, concluding that the expert's statistical calculations were not responsive to the question of whether the failure to administer t-PA more likely than not caused the plaintiff's injuries.

On appeal, the First Circuit noted that “the scope of a Daubert hearing is not limited to an appraisal of an expert's credentials and techniques but also entails an examination of his conclusions to determine whether they flow rationally from the methodology employed.” Id. at *24. In responding to the plaintiff's claim that his expert was well qualified and relied on acceptable science, the court stated that the issue was not with the expert's credentials or the reliability of his methods, but with the analytical gap between his data and opinions.

Statistical Data

The opinions of the plaintiff's expert rested on statistical data from scientifically reliable sources. The expert first used odds ratios, or ratios of the odds of an adverse outcome, between a group of patients who had received t-PA and a placebo group. Some of these ratios ranged higher than 50% and the expert used them to opine that the plaintiff more likely than not would have recovered had he received the drug. The court pointed out the expert's flawed assumption regarding the odds ratios by noting that “[w]hen a person's chances of a better outcome are 50% greater with treatment (relative to the chances of those who were not treated), that is not the same as a person having a greater than 50% chance of experiencing the better outcome with treatment. The latter meets the required standard for causation; the former does not.” Id. at *27-28. The court illustrated this point by noting that “suppose that studies have shown that 10 out of a group of 100 people who do not eat bananas will die of cancer, as compared to 15 out of a group of 100 who do eat bananas. The banana-eating group would have an odds ratio of 1.5 or a 50% greater chance of getting cancer than those who eschew bananas. But this is a far cry from showing that a person who eats bananas is more likely than not to get cancer.” Id. at *28. In other words, the court concluded that although the odds ratios establish that the plaintiff would have had a greater chance of recovering had he received the t-PA, they do not provide support for the proposition that, had he received the drug, there was a greater than 50% chance that he would have recovered.

The expert also relied on absolute efficacy rates, which in some cases exceeded 50%, and asserted that they were sufficient to prove that the plaintiff's injuries were likely caused by the defendants' failure to administer t-PA. Specifically, he “stated that 52.4% of patients receiving t-PA recovered as measured by a particular scale. Based on this percentage, he suggested that had the plaintiff received t-PA, he more likely than not would have avoided stroke-related injuries.” Id. at *31. Again, the court pointed to the flaws in the expert's reasoning. It noted that his conclusion overlooked the 45.2% of people who recovered even without the benefit of t-PA. The court also noted that “[f]or a small number of patients who would not otherwise have recovered, t-PA would offer some advantage, but for the majority of patients whose conditions would not improve on their own, the administration of the drug would make no difference.” Id. at *31. The court ultimately concluded, therefore, that “[t]he methods that [the plaintiff's expert] employed and the data that he presented were simply too distant from the conclusion that he drew, thus negating an adequate fit.” Id. at *32.

Practical Implications

The First, Fifth and Seventh Circuits' approach in the above-referenced cases is significant because the courts specifically examined the connection between an expert's opinion and underlying data in the context of Daubert's “fit” analysis and used the disconnect between the expert's data and opinion as the basis for precluding testimony. Under this minority, a district court will likely give greater scrutiny to a disconnect between an expert's opinion and underlying data than it would under the “fit” analysis performed by the majority of courts. The minority approach, therefore, provides attorneys with a stronger basis for challenging an opposing expert's testimony on the ground that the testimony is not supported by the underlying data. Consequently, even in jurisdictions that have not adopted this alternative approach to Daubert's “fit” requirement, attorneys should look to frame their challenges to expert testimony under the standard applied by the First, Fifth, and Seventh Circuits.

James H. Rotondo, a member of this newsletter's Board of Editors, is co-chair of the Commercial Litigation Department at Day Pitney LLP, in Hartford, CT. He focuses his practice on product liability, tort and insurance litigation. Michael P. Pohorylo is an associate in the firm.