that below a dose of 10 rems, there is no direct evidence of a causal relationship between exposure to ionizing radiation and cancer induction. National Research Council, Committee on the Biological Effects of Ionizing Radiation, Health Effects of Exposure to Low Levels of Ionizing Radiation at 7 (National Academy Press 1990) ("BEIR V") (noting that "assessment of the carcinogenic risks that may be associated with low doses of radiation entails extrapolation from effects observed at doses larger than 0.1 Gy [(10 rems)] and is based on assumptions about the relevant dose effect relationships and the underlying mechanisms of carcinogenesis"). To the extent that Dr. Winters presumed a dose of greater than 10 rem, without having gathered reliable data to support that presumption, his differential diagnosis has a high probability of being incorrect.
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.
II. Dr. Theodor Sterling
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.
. . .