Conn. R. Evid. 7-4
Conn. Code. Evid. 7-4
COMMENTARY
(a) Opinion testimony by experts.
Connecticut case law requires disclosure of the "factual basis'' underlying an expert witness' opinion before the expert witness may render that opinion. See Borkowski v. Borkowski, 228 Conn. 729, 742, 638 A.2d 1060 (1994); State v. John, 210 Conn. 652, 677, 557 A.2d 93, cert. denied, 493 U.S. 824, 110 S. Ct. 84, 107 L. Ed. 2d 50 (1989); State v. Asherman, 193 Conn. 695, 716, 478 A.2d 227 (1984), cert. denied, 470 U.S. 1050, 105 S. Ct. 1749, 84 L. Ed. 2d 814 (1985); see also Practice Book § 13-4(b) (1); Going v. Pagani, 172 Conn. 29, 34, 372 A.2d 516 (1976). Subsection (a) incorporates this principle by requiring the party offering the evidence to show that the expert's opinion rests upon an adequate factual foundation. This requirement applies whether the expert's opinion is based on personal knowledge or secondhand facts made known to the expert at or before trial. E.g., State v. John, supra, 676-78 (secondhand data customarily relied on by other experts); Going v. Pagani, supra, 32 (firsthand observation); Floyd v. Fruit Industries, Inc., 144 Conn. 659, 666, 136 A.2d 918 (1957) (secondhand facts made known to expert through use of hypothetical question).
Subsection (a) contemplates that disclosure of the "foundational'' facts will, in most cases, occur during the examination undertaken by the party calling the expert and before the expert states his or her opinion. The requirement of preliminary disclosure, however, is subject to the trial court's discretionary authority to admit evidence upon proof of connecting facts or subject to later proof of connecting facts. Section 1-3(b); see Schaefer & Co. v. Ely, 84 Conn. 501, 509, 80 A. 775 (1911). Nothing in subsection (a) precludes further exploration into the factual basis for the expert's opinion during cross-examination of the expert. Whether sufficient facts are shown as the foundation for the expert's opinion is a preliminary question to be decided by the trial court. Liskiewicz v. LeBlanc, 5 Conn. App. 136, 141, 497 A.2d 86 (1985); see Section 1-3(a).
The admissibility of expert testimony rendered by a physician- whether a treating or nontreating physician-is governed by the same evidentiary standard applied to the testimony of expert witnesses generally. George v. Ericson, 250 Conn. 312, 317, 736 A.2d 889 (1999), overruling Brown v. Blauvelt, 152 Conn. 272, 274, 205 A.2d 773 (1964).
(b) Bases of opinion testimony by experts.
Subsection (b) allows an expert witness to base his or her opinion on "facts'' derived from one or more of three possible sources. First, the expert's opinion may be based on facts "perceived by'' the expert at or before trial, in other words, facts the expert observes firsthand. E.g., State v. Conroy, 194 Conn. 623, 628-29, 484 A.2d 448 (1984); Donch v. Kardos, 149 Conn. 196, 201, 177 A.2d 801 (1962); Wilhelm v. Czuczka, 19 Conn. App. 36, 42, 561 A.2d 146 (1989). For example, a treating physician often will base an expert opinion on observations made by the physician [made] while examining the patient. See generally State v. McClary, 207 Conn. 233, 236- 38, 541 A.2d 96 (1988).
Second, the expert's opinion may be based on facts "made known'' to the expert at trial. This category includes facts learned by the expert while attending the trial and listening to the testimony of other witnesses prior to rendering his or her own opinion. See DiBiase v. Garnsey, 106 Conn. 86, 89, 136 A. 871 (1927). It also includes facts presented to the expert in the form of a hypothetical question. See, e.g., Keeney v. L & S Construction, 226 Conn. 205, 213, 626 A.2d 1299 (1993); State v. Auclair, 33 Conn. Sup. 704, 713, 368 A.2d 235 (1976).
Finally, the expert's opinion may be based on facts, of which the expert has no firsthand knowledge, made known to the expert before trial, regardless of the admissibility of those facts themselves. See, e.g., State v. Gonzalez, 206 Conn. 391, 408, 538 A.2d 210 (1988) (expert's opinion based on autopsy report of another medical examiner); State v. Cosgrove, 181 Conn. 562, 584, 436 A.2d 33 (1981) (expert's opinion derived from reports that included observations of other toxicologists).
Although the factual basis for expert opinions resting on the first two sources of information (i.e., facts gleaned from firsthand observation or facts made known to the expert at trial normally do not encounter obstacles to admissibility, case law is inconsistent with respect to the admissibility of expert opinion based on facts in the last category (i.e., facts themselves inadmissible at trial and as to which the expert has no firsthand knowledge). In accordance with the modern trend in Connecticut, subsection (b) provides that an expert may offer an opinion based on facts that are not themselves admissible if those facts are of a type customarily relied on by experts in the particular field in forming their opinions. E.g., George v. Ericson, supra, 250 Conn. 324-25; State v. Gonzalez, supra, 206 Conn. 408; State v. Cuvelier, 175 Conn. 100, 107-108, 436 A.2d 33 (1978). Facts of this nature may come from sources such as conversations, informal opinions, written reports and data compilations. Whether these facts are of a type customarily relied on by experts in forming opinions is a preliminary question to be decided by the trial court. See Section 1-3(a).
In a criminal case, when an expert opinion is based on facts not in evidence, the court and parties should be aware of constitutional concerns. See State v. Singh, 59 Conn. App. 638, 652, 757 A.2d 1175 (2000) (opinion based on information provided by others does not violate confrontation clause if expert is available for cross-examination concerning nature and reasonableness of reliance), rev'd on other grounds, 259 Conn. 693, 793 A.2d 226 (2002); cf. In re Barbara J., 215 Conn. 31, 43-44, 574 A.2d 203 (1990) (termination of parental rights). This added requirement, which is not included in subsection (b) as an independent prerequisite under the Code, has been mentioned in dicta in civil cases as well. See R.I. Pools, Inc. v. Paramount Concrete, Inc., 149 Conn. App. 839, 849, 89 A.3d 993 ("expert may give an opinion based on sources not in themselves admissible in evidence, provided [1] the facts or data not in evidence are of a type reasonably relied on by experts in the particular field, and [2] the expert is available for cross-examination concerning his or her opinion'' [internal quotation marks omitted]), cert. denied, 312 Conn. 920, 94 A.3d 1200 (2014); Birkhamshaw v. Socha, 156 Conn. App. 453, 484, 115 A.3d 1, cert. denied, 317 Conn. 913, 116 A.3d 812 (2015).
Subsection (b) expressly states that the facts forming the basis of the expert opinion are not thereby made admissible as substantive evidence (i.e., for their truth) unless otherwise admissible as such under other provisions of the Code. See Milliun v. New Milford Hospital, 310 Conn. 711, 726-28, 80 A.3d 887 (2013). Thus, subsection (b) does not constitute an exception to the hearsay rule or any other exclusionary provision of the Code. However, because subsection (a) requires disclosure of a sufficient factual basis for the expert's opinion, and because the cross-examiner often will want to explore the expert's factual basis further, subsection (b) does not preclude the trial court, in its discretion, from admitting the underlying facts relied on by the expert for the limited purpose of explaining the factual basis for the expert's opinion. DeNunzio v. DeNunzio, 151 Conn. App. 403, 413, 95 A.3d 557 (2014), aff'd on other grounds, 320 Conn. 178, 128 A.3d 901 (2016).
(c) Hypothetical questions.
Subsection (c) embraces the common-law rule concerning the admissibility of a hypothetical question and, necessarily, the admissibility of the ensuing expert's opinion in response to the hypothetical question. Floyd v. Fruit Industries, Inc., supra, 144 Conn. 666; accord Shelnitz v. Greenberg, 200 Conn. 58, 77, 509 A.2d 1023 (1986); Schwartz v. Westport, 170 Conn. 223, 225, 365 A.2d 1151 (1976). In accordance with case law, subsection (c) recognizes that the hypothetical question must contain the essential facts of the case; see State v. Gaynor, 182 Conn. 501, 509-10, 438 A.2d 739 (1980); see also Keeney v. L & S Construction, supra, 226 Conn. 213 ("the stated assumptions on which a hypothetical question is based must be the essential facts established by the evidence''); but need not contain all the facts in evidence. E.g., Donch v. Kardos, supra, 149 Conn. 201; Stephanofsky v. Hill, 136 Conn. 379, 384, 71 A.2d 560 (1950).
Subsection (c) states the rule concerning the framing of hypothetical questions on direct examination. See, e.g., Schwartz v. Westport, supra, 170 Conn. 224-25. The rules governing the framing of hypothetical questions on direct examination and for the purpose of introducing substantive evidence are applied with increased liberality when the hypothetical question is framed on cross-examination and for the purpose of impeaching and testing the accuracy of the expert's opinion testimony given on direct examination. See, e.g., State v. Gaynor, supra, 182 Conn. 510-11; Kirchner v. Yale University, 150 Conn. 623, 629, 192 A.2d 641 (1963); Livingstone v. New Haven, 125 Conn. 123, 127-28, 3 A.2d 836 (1939); Rice v. Dowling, 23 Conn. App. 460, 465, 581 A.2d 1061 (1990), cert. denied, 217 Conn. 805, 584 A.2d 1190 (1991). Common law shall continue to govern the use of hypothetical questions on cross-examination.