The opinion of the court was delivered by: RAMBO
On April 2, 1996, the court issued a memorandum of law ruling in part on Defendants' motion in limine to exclude Plaintiffs' medical causation experts. Remaining before the court is the balance of that motion, including challenges to the proffered testimony of Thomas Winters, Theodor Sterling, Sigmund Zackrzewski, David Lochbaum, Joseph Cardinale and Jose Galindo, Jr. A statement of the factual background of the case and discussion of the legal standards governing the admission of expert scientific testimony can be found in this court's memorandum of law dated January 6, 1996. In re TMI Litigation Cases Consolidated II, 911 F. Supp. 775 (M.D. Pa. 1996). The court will now reach the remaining in limine challenges.
Dr. Winters is a medical doctor, board certified in internal and occupational medicine, (Tr. at 1206), and eligible for certification in infectious diseases. He is the medical director for employee health, and director of a clinic on occupational medicine at Carney Hospital in Boston, Massachusetts. (Tr. at 1199, 1211.) Dr. Winters is also a Clinical Associate Professor of Medicine at the Boston University School of Medicine and a Visiting Lecturer in Occupational Medicine at the Harvard University School of Public Health. (2/27/95 Winters Rpt. at 1.) Based upon his review of all of the test Plaintiffs' medical records, and his personal examination of the living test Plaintiffs, Dr. Winters offers his opinion that each of the test Plaintiffs' neoplasms were caused by their exposure to ionizing radiation during the TMI accident. Defendants' specific challenges relating to the admissibility of Dr. Winters' proffered testimony will be addressed in the context of the court's Daubert/Paoli II analysis.
A. The Daubert/Paoli II Analysis
1. Is the Methodology Based Upon a Testable Hypothesis?
When asked during his deposition whether he started his evaluation with a hypothesis, Dr. Winters replied that he "started with no hypothesis." (6/23/95 Winters Dep. at 72.) Dr. Winters distinguished his study from general epidemiological studies and stated that without a hypothesis, he simply applied his methodology to each case. (Id. at 73.) According to the Paoli II court, "differential diagnosis can be considered to involve the testing of a falsifiable hypothesis . . . through an attempt to rule out alternative causes." Paoli II 35 F.3d 717, 758 (3d Cir. 1994). To determine whether Dr. Winters tested his hypothesis, the court must determine whether he performed a differential diagnosis. According to Dr. Winters' deposition testimony, he reviewed the medical records of all of the test Plaintiffs and performed physical examinations upon those test Plaintiffs that are still living. (6/23/95 Winters Dep. at 72, 73, 81-82.) Pursuant to Paoli II, Dr. Winters examined the information necessary to make a differential diagnosis. Paoli II, 35 F.3d at 762. As such, whether or not Dr. Winters realized it, his differential diagnosis was essentially an attempt to verify or falsify the hypothesis that the TMI Plaintiffs developed their neoplasms as a result of exposure to ionizing radiation during the TMI accident. The court finds that to the extent that it is relevant to making a differential diagnosis, Dr. Winters' methodology is based upon a testable hypothesis. This factor will weigh in favor of the admission of the proffered testimony.
2. Has the Methodology Been Subject to Peer Review?
At the in limine hearing, Dr. Winters testified that his methodology, as applied in a radiation case, has not been subject to peer review. (Tr. at 1355-56.) Insofar as Dr. Winters methodology is a differential diagnosis, the Third Circuit has recognized that "differential diagnosis generally is a technique that has widespread acceptance in the medical community, has been subject to peer review, and does not frequently lead to incorrect results . . . . " Despite the general presumption that a differential diagnosis methodology has been subject to peer review, Dr. Winters testified that his radiation causation differential diagnosis has not been subject to peer review. In light of Paoli II the court finds this factor to be of diminished relevance in the context of a differential diagnosis. However, to the extent that it is relevant, this factor will weigh against the admission of the proffered testimony.
3. Is There a Known or Potential Rate of Error?
Although a differential diagnosis "does not frequently lead to incorrect results," Paoli II, 35 F.3d at 758, "to the extent that a doctor utilizes standard diagnostic techniques in gathering this information, the more likely" the methodology will be found to be reliable. Id. Defendants' arguments with respect to the potential rate of error in Dr. Winters' methodology relate to the diagnostic techniques that he used and failed to use.
First, Defendants contend that Dr. Winters based his opinion in part upon the unfounded assumption that Plaintiffs were exposed to 10 to 300 rems of radiation, and that exposure anywhere in that range would produce the kinds of effects that were observed. During his deposition, Dr. Winters explained that he "knew the dose was above a hundred rems, and figured that even if it dropped down to the 50- or 10- rem area, [his] . . . opinion would still be the same." (6/23/95 Winters Dep. at 80.) It is unclear how Dr. Winters "knew" the dose rate. In his deposition Dr. Winters indicated that prior to conducting his analysis he "had reviewed the Hatch articles in American Journal of Public Health, American Journal of Epidemiology . . . [and] had reviewed pictures of trees and had heard that Dr. Gunckel had evaluated and Dr. Shevchenko had looked at dendritic samples that showed a significant dose of radiation."
(Id. at 76.)
Next, Defendants contend that data from the study of populations exposed to radiation indicate that where a study fails to consider factors such as a specific organ dose, the effect of a person's age at the time of exposure, the time since exposure, and the effect of the sex of the person on their risk of developing the type of cancer they exhibit, any conclusion regarding a causal relation between radiation exposure and a given health outcome is subject to substantial error. The International Commission on Radiation Protection ("ICRP")
has observed that "the relationship between the probability of stochastic
effects and equivalent dose is found also to depend on the organ or tissue irradiated. It is therefore appropriate to define a further quantity, derived from equivalent dose, to indicate the combination of different doses to several different tissues
in a way which is likely to correlate well with the total of stochastic effects." ICRP Pub. 60, Annals of the ICRP, "1990 Recommendations of the International Commission on Radiological Protection" 6 (Pergamon Press 1991) (footnote added). This ICRP report also supports Defendants' assertion that sex and age at the time of exposure are "biological factors affecting cancer induction" following exposure to ionizing radiation, that should be considered when making a causal inference regarding radiation exposure and cancer induction. Id. at 120-22.
The court, as it did with this component of Dr. Fajardo's methodology, finds it difficult to quantify the effect that the omission of the referenced data might have had upon the overall analysis. It is apparent that the omission of this data introduced at least a moderately high potential rate of error into the final diagnosis. In Paoli II, the Third Circuit held that where a physician offered a differential diagnosis which found a causal link between PCB exposure and subsequent health effects, and where the defendants then offered an alternative cause for the plaintiffs' health effects, the expert "had to offer a good explanation as to why their conclusion remained reliable." Paoli II, 35 F.3d at 762. To a limited extent, the court finds Dr. Winters' failure to consider certain data, Defendants' direct challenge on that subject, and Dr. Winters' subsequent failure to offer a "good explanation" for the omission to be analogous to the Paoli II scenario. However, where the Third Circuit has clearly expressed its opinion as to the general reliability of differential diagnosis, and the more liberal standard under which this court must evaluate such a diagnosis, the court is finds that the failure to consider certain potentially relevant data goes to the weight of the testimony.
Because the court is unable to quantify the effect that Dr. Winters' omissions had upon the reliability of his findings, the court will weigh this factor neither in favor nor against the admission of the proffered testimony.
4. Were There Standards Controlling the Technique's Operation?
Defendants contend that the lack of standards controlling Dr. Winters' differential diagnosis is evidenced by his "consistently ignoring epidemiologic data that was not consistent with his ultimate conclusions on causation," and his misplaced reliance on toxicological texts as providing the standards governing his methodological approach. (Defs.' Findings at 130-31.) During his deposition, Dr. Winters provided the following statement of his methodology:
I used the methodology of occupational, standard toxicology, occupational health evaluations, where you look at a condition, you look at the dose, the dose response, you make sure there's adequate latency period, you make sure there are no other confounding contributing factors. You make sure that the illness is, in fact, caused, or the disease is, in fact, caused by the agent, which is radiation in this case, and you make a logical deduction at the end of that.
6/23/95 Winters Dep. at 72.) The court finds Dr. Winters' failure to consider the importance of calculating a specific organ dose to evidence an absence of a standard controlling the operation of his technique. However, the court also finds evidence on the record that Dr. Winters did employ some important standards such as considering relevant latency periods and considering possible confounding factors. Accordingly, the court finds that because there is evidence that some important standards were employed, Defendants' challenges go to the weight, and not the admissibility, of the proffered testimony. This factor will weigh in favor of the admission of the proffered testimony.
5. Is the Methodology Generally Accepted?
It is unquestionable that as a general proposition, the use of differential diagnosis in the medical field is well accepted. The issue, though, is whether it is generally accepted to infer a causal relationship between a possible exposure to ionizing radiation and a subsequent health effect based solely upon a differential diagnosis. In connection with its evaluation of the Fajardo proffer, the court found that such an inference is not generally accepted. In re TMI, Mem. Op. at 100-01 (M.D. Pa. April 2, 1996) (quoting the NCRP's finding that "'it is not possible, on the basis of medical evaluation, to unequivocally prove or disprove a claim that a specific malignancy was caused by a specific radiation exposure'"). Despite this finding, the court found this factor to weigh in favor of the admission of the Fajardo proffer. The court found that through his report and testimony, Dr. Fajardo did not represent that he had "unequivocally proven" that Plaintiffs' neoplasms were causally related to radiation exposure during the TMI accident. Dr. Fajardo's conclusion is based upon a presumption that other of Plaintiffs' experts will establish the actual exposure to the requisite dose.
Accordingly, insofar as the court must presume at this stage that Dr. Winters' proffered testimony will be supported at trial by evidence that the test Plaintiffs were exposed to in excess of 10 rems of ionizing radiation; and, insofar as other experts will present testimony that provides "another basis for judgment as to causation," NCRP Stmt. No. 7 at 1, the court finds that this factor weighs in favor of the admission of the proffered testimony.
6. Is There a Relationship Between the Technique and Methods That are Established to be Reliable?
Defendants' argue that Dr. Winters' methodology bears little resemblance to methods established to be reliable. While Dr. Winters' methodology does not closely resemble established methods, it does bear some resemblance. To the extent that Dr. Winters has made a medical differential diagnosis, his methodology comports closely with established and reliable methods. Conversely, to the extent that in making a causal inference he is actually engaged in a risk assessment, Dr. Winters' methodology bears little resemblance to established methods. On the balance, the court finds that because his methodology bears some relationship to established methods, this factor weighs in favor of the admission of the proffered testimony.
7. What are the Qualifications of the Expert Based Upon the Methodology?
Defendants argue that Dr. Winters is not qualified to testify as an expert in radiation health effects. Specifically, Defendants contend that Dr. Winters' review of scientific literature on the epidemiologic studies of populations exposed to radiation does not establish him as an expert in the field. In addition, Defendants note that one other district court has found that Dr. Winters was "not qualified to testify on either the general or specific causal relationship between radiation and the induction of [acute lymphocytic leukemia]." Whiting v. Boston Edison Co., 891 F. Supp. 12, 25 (D. Ma. 1995). The Third Circuit recently reaffirmed its liberal approach regarding the qualifications factor of the Rule 702 analysis in Holbrook v. Lykes Bros. Steamship Co., 1996 U.S. App. LEXIS 5354, No. 94-2148, slip. op. at 10 (3d Cir. March 21, 1996). Specifically, the Third Circuit explained that:
Because of our liberal approach to admitting expert testimony, most arguments about an expert's qualifications relate more to the weight to be given the expert's testimony, than to its admissibility. Thus, witnesses may be competent to testify as experts even though they may not, in the court's eyes, be the "best" qualified. Who is "best" qualified is a matter of weight upon which reasonable jurors may disagree. . . . Following this logic, it is an abuse of discretion to exclude testimony simply because the trial court does not deem the proposed expert to be the best qualified or because the proposed expert does not have the specialization that the court considers most appropriate.
Holbrook, slip. op. at 10. Dr. Winters certainly may not be the "best" qualified expert in this area. Moreover, it cannot be taken lightly that he has been precluded from giving the same type of testimony in other litigation on the basis of his lack of qualifications. Nevertheless, Dr. Winters is a practicing physician who has demonstrated at least a basic knowledge of the relevant scientific principles. Pursuant to Holbrook and Paoli II this court is bound to liberally construe the qualifications prong of the Rule 702 analysis. Accordingly, this factor weighs in favor of the admission of the proffered testimony.
8. Are There Non-Judicial Uses of the Methodology?
Dr. Winters performs differential diagnoses in a variety of settings connected with his medical practice. It is questionable whether the specific methodology used in this case to determine whether radiation caused specific cancers has been employed outside of litigation. This factor will weigh neither in favor nor against the admission of the proffered testimony.
Based upon its Rule 702 reliability analysis, the court finds the proffered testimony of Dr. Winters' to be scientifically reliable.
B. Rule 702 Fit, Rule 703 and Rule 403 Analyses
If permitted, Dr. Winters will offer his opinion that each of the test Plaintiffs' neoplasms were induced by their exposure to ionizing radiation during the Three Mile Island Accident. Presuming that Plaintiffs present evidence that corroborates Dr. Winters' assumption regarding the dose of radiation received by the test Plaintiffs, Dr. Winters' causation testimony will have the requisite "fit" with the case. At this stage, the court finds that Dr. Winters' proffered testimony "fits."
With respect to Rule 703, the court finds that Dr. Winters relied upon the type of data that a medical professional would rely upon in making a differential diagnosis. Defendants' challenges with respect to data that Dr. Winters failed to consider go to the weight of his testimony. Finally, the court finds that the proffered testimony is not so confusing as to warrant exclusion pursuant to Rule 403. Based upon the foregoing, the court will admit the proffered testimony of Dr. Winters.
Dr. Sterling is a Professor on the faculty of Applied Sciences in the School of Computing Science at Simon Fraser University in Burnaby, British Columbia, Canada. Before the court is Dr. Sterling's initial report, dated April 25, 1995, and a supplemental affidavit, dated February 2, 1996. In accordance with its memorandum of law dated April 2, 1996, the court will exclude Dr. Sterling's untimely 1996 affidavit. Accordingly, the court will proceed with its evaluation of the Sterling proffer based upon the timely filed report and his in limine testimony to the extent it is not beyond the scope of his report.
A. The Proffered Testimony
Dr. Sterling testified at the hearings that he performed an epidemiological analysis on certain groups of data relating to the TMI area. (Tr. at 1090.) In the introduction to his report, Dr. Sterling gives the following brief discussion of each cohort and the statistical analysis performed on the cohort:
The Hesteco Garment Workers: A cohort of 69 women employed by Hesteco Manufacturing Co. and present at the factory premises at the time of the accident. Ten women have developed cancer since then. This number of cancers is greater than would be expected had the cohort developed cancer at the same incidence rate as a comparable group of women selected from the general population.
The Harrisburg School Children: A cohort consisting of 1991 students attending four Harrisburg elementary schools at the time of the accident. At least six of these students have developed cancer. This number of cancers is greater than would be expected had the cohort developed cancer at the same ...