Mass. R. Evid. 702
A witness who is qualified as an expert by knowledge, skill, experience, training, or education may testify in the form of an opinion or otherwise if
Mass. Guid. Evid. 702
Introduction. This section, which is based upon Fed. R. Evid. 702, reflects Massachusetts common law. The proponent of expert testimony must establish the foundational requirements for admissibility, and the judge, as the "gatekeeper" of the evidence, must make a threshold determination that those requirements have been met before the testimony goes to the jury. See Commonwealth v. Davis, 487 Mass. 448, 453 (2021); Commonwealth v. Hinds, 487 Mass. 212, 218 (2021); Commonwealth v. Barbosa, 457 Mass. 773, 783 (2010), cert. denied, 563 U.S. 990 (2011).
"[T]he touchstone of admissibility is reliability." Commonwealth v. Sands, 424 Mass. 184, 185 (1997). There are two methods by which the judge may satisfy the gatekeeper duty to ensure that principles or methods upon which expert witness testimony is based are reliable: (1) the Frye test, i.e., general acceptance in the relevant scientific community, see Frye v. United States, 293 F. 1013 (D.C. Cir. 1923), or (2) a Daubert - Lanigan analysis, see Daubert v. Merrell Dow Pharms., Inc., 509 U.S. 579, 585-595 (1993), and Commonwealth v. Lanigan, 419 Mass. 15, 24-26 (1994). The principal difference between the Federal rules and the Massachusetts approach to reliability is that in Massachusetts, the proponent of expert testimony may establish reliability simply by demonstrating that the underlying principles or methodologies are generally accepted by the relevant scientific community. See Davis, 487 Mass. at 454-455; Commonwealth v. Patterson, 445 Mass. 626, 640-641 (2005). In the Federal courts, by contrast, the "rigid" Frye general acceptance test was supplanted by Fed. R. Evid. 702 and the Daubert test, under which a judge must consider five nonexclusive factors in assessing reliability (even though widespread acceptance remains an "important factor" in the Daubert analysis). Daubert, 509 U.S. at 588, 593-594. Recognizing that strict adherence to the Frye test could result in reliable evidence being kept from the finder of fact, the Supreme Judicial Court in Lanigan adopted the Daubert test as an alternative method of establishing the reliability of expert testimony. Davis, 487 Mass. at 453-454.
In both Massachusetts and Federal courts, the framework used for testing reliability is specifically described as "flexible." Kumho Tire Co. v. Carmichael, 526 U.S. 137, 141 (1999) ("the test of reliability is 'flexible,' and Daubert 's list of specific factors neither necessarily nor exclusively applies to all experts or in every case"); Canavan's Case, 432 Mass. 304, 314 n.5 (2000) ("Application of the Lanigan test requires flexibility. Differing types of methodology may require judges to apply differing evaluative criteria to determine whether scientific methodology is reliable. In the Lanigan case, we established various guideposts for determining admissibility including general acceptance, peer review, and testing.").
Hearing. If a party opposes the admission of expert testimony because one or more of the foundational requirements have not been met, the party may file a motion in limine to prohibit its admission and request a hearing. Commonwealth v. Barbosa, 457 Mass. 773, 783 (2010), cert. denied, 563 U.S. 990 (2011). An evidentiary hearing is not always necessary to comply with Commonwealth v. Lanigan, 419 Mass. 15 (1994). See Palandjian v. Foster, 446 Mass. 100, 111 (2006); Vassallo v. Baxter Healthcare Corp., 428 Mass. 1, 1-13 (1998) (trial judge properly relied on affidavits and transcripts of testimony from other cases). If a theory or methodology has been firmly established as reliable in the past, the judge may take judicial notice of its reliability, Commonwealth v. Davis, 487 Mass. 448, 454-455 (2021), but a Daubert - Lanigan hearing may be necessary to test the continuing validity of a generally accepted theory or its application in a novel manner. See Id. at 455; Commonwealth v. Shanley, 455 Mass. 752, 763 n.15 (2010) (prudent for trial judge to conduct an evidentiary hearing in connection with expert testimony about dissociative amnesia because of "the evolving nature of scientific and clinical studies of the brain and memory"). If the party does not file a pretrial motion requesting a Daubert - Lanigan hearing to challenge the reliability of the methodology, the issue is waived on appeal. Commonwealth v. Wilkerson, 486 Mass. 159, 172 (2020). A trial judge's decision on whether expert witness evidence satisfies gatekeeper reliability is reviewed on appeal under an abuse of discretion standard. See General Elec. Co. v. Joiner, 522 U.S. 136, 141-143 (1997); Commonwealth v. Rintala, 488 Mass. 421, 425-426 (2021); Canavan's Case, 432 Mass. 304, 311-312 (2000).
Five Foundation Requirements. The proponent of expert witness testimony has the burden of establishing the five foundational requirements for admission. See Commonwealth v. Barbosa, 457 Mass. 773, 783 (2010), cert. denied, 563 U.S. 990 (2011). First, the proponent must establish that the expert witness testimony will assist the trier of fact. See Commonwealth v. Francis, 390 Mass. 89, 98 (1983); Commonwealth v. Rodziewicz, 213 Mass. 68, 69-70 (1912). Second, the proponent must demonstrate that the witness is qualified as an expert in the relevant area of inquiry. See Commonwealth v. Frangipane, 433 Mass. 527, 535-536 (2001); Commonwealth v. Boyd, 367 Mass. 169, 182 (1975). Third, the proponent must demonstrate that the facts or data in the record are sufficient to enable the witness to give an opinion that is not merely speculation. See Lightlab Imaging, Inc. v. Axsun Techs., Inc., 469 Mass. 181, 191 (2014). Fourth, the expert opinion must be based on a body of knowledge, a principle, or a method that is reliable. Commonwealth v. Lanigan, 419 Mass. 15, 26 (1994). Fifth, the proponent must demonstrate that the expert's opinion reflects a reliable application of the body of knowledge, the principle, or the method to the particular facts of the case. See Commonwealth v. Patterson, 445 Mass. 626, 645-648 (2005); Commonwealth v. McNickles, 434 Mass. 839, 850 (2001).
Each of these five foundation requirements is a preliminary question of fact for the trial judge to determine. See Section 104(a), Preliminary Questions: In General. In making these preliminary determinations, the trial judge may be required to resolve disputes as to the credibility of witnesses. Patterson, 445 Mass. at 647-648. Although the trial judge has "broad discretion" in making these determinations, Commonwealth v. Robinson, 449 Mass. 1, 5 (2007), expert witness testimony should not be deemed unreliable simply because there is a disagreement of opinion or in the level of confidence among the experts. See Commonwealth v. Torres, 442 Mass. 554, 581 (2004).
Expert testimony may not be excluded because the judge disagrees with the expert's opinion or finds the testimony unpersuasive. See Commonwealth v. Roberio, 428 Mass. 278, 281 (1998) ("Once the expert's qualifications were established and assuming the expert's testimony met the standard of Commonwealth v. Lanigan, 419 Mass. 15 [1994], the issue of credibility was for a jury, not the judge."). When an expert's opinion is based on the analysis of complex facts, the failure of the expert to account for all the variables goes to its weight and not its admissibility. Salvas v. Wal-Mart Stores, Inc., 452 Mass. 337, 359-360 (2008). See Id. at 351-360 (expert witness with doctorate in psychology and mathematics used statistical methods to evaluate large body of employee records to account for missing records and to opine that employer had wrongfully deprived employees of compensation).
First Foundation Requirement: Assistance to the Trier of Fact. "The role of an expert witness is to help jurors interpret evidence that lies outside of common experience." Commonwealth v. Tanner, 45 Mass. App. Ct. 576, 581 (1998). Thus, expert testimony may be excluded when it will not assist the jury. See Commonwealth v. Tolan, 453 Mass. 634, 648 (2009) (trial judge has discretion "to preclude expert testimony on commonly understood interrogation methods"). Expert witness testimony also may be excluded because it is cumulative, Anthony's Pier Four, Inc. v. HBC Assocs., 411 Mass. 451, 482 (1991), or because it does not fit the facts of the case. See Ready, petitioner, 63 Mass. App. Ct. 171, 179 (2005) (concluding that diagnostic test known as the Abel Assessment of Sexual Interest was of no value to fact issues facing jury). See generally Section 403, Excluding Relevant Evidence for Prejudice, Confusion, Waste of Time, or Other Reason. Finally, expert witness testimony may be excluded as not probative of a material fact in dispute and thus of no assistance to the jury when it amounts to a mere guess or conjecture. Kennedy v. U-Haul Co., 360 Mass. 71, 73-74 (1971); Commonwealth v. Acosta, 81 Mass. App. Ct. 836, 843 (2012). See also Section 402, General Admissibility of Relevant Evidence. There are circumstances, however, in which an expert witness's opinion as to a possibility will have probative value. See Commonwealth v. Federico, 425 Mass. 844, 852 (1997) (expert permitted to offer opinion that absence of physical trauma to child's genital area was not inconsistent with sexual abuse).
Second Foundation Requirement: Qualifications of the Expert. "The crucial issue in determining whether a witness is qualified to give an expert opinion is whether the witness has sufficient education, training, experience and familiarity with the subject matter of the testimony" (quotations and citation omitted). Commonwealth v. Richardson, 423 Mass. 180, 183 (1996). See Adoption of Hugo, 428 Mass. 219, 232-234 (1998) (licensed clinical social worker); Commonwealth v. Hoime, 100 Mass. App. Ct. 266, 271-272 (2021) (toxicologist); Custody of Michel, 28 Mass. App. Ct. 260, 266 (1990) (investigator appointed under G. L. c. 119, § 24). See also Cronin v. McCarthy, 22 Mass. App. Ct. 448, 451 n.1 (1986) (collecting cases in which experts without specialized training were deemed qualified based on knowledge and experience). A preliminary determination that an expert witness is qualified does not always require an explicit ruling on the record by the judge. However, if a formal ruling is made, it should be made outside the hearing of the jury. Richardson, 423 Mass. at 184.
The trial judge, acting as the gatekeeper, must enforce boundaries between areas of expertise within which the expert is qualified and areas that require different training, education, and experience. Whether an expert qualified in one subject area is qualified in a related subject area "will depend on the circumstances of each case, and, where an expert has been determined to be qualified, questions or criticisms as to whether the basis of the expert's opinion is reliable go to the weight, and not the admissibility, of the testimony." Commonwealth v. Crouse, 447 Mass. 558, 569 (2006) (noting that there must always be a first time for every expert witness). See Commonwealth v. Frangipane, 433 Mass. 527, 535 (2001) (social worker was qualified to testify as an expert witness that abused children may experience dissociative memory loss and recovered memory but was not qualified to testify about how trauma victims store and retrieve or dissociate memories); Commonwealth v. Bouley, 93 Mass. App. Ct. 709, 714-715 (2018) (EMT qualified to opine that defendant had overdosed on opioids). Questions posed to a witness on cross-examination may qualify the witness to offer expert testimony on redirect examination. Motsis v. Ming's Supermkt., Inc., 96 Mass. App. Ct. 371, 381-382 (2019).
Third Foundation Requirement: Knowledge of Sufficient Facts or Data in the Record. The trial judge must determine whether the proponent of expert testimony has demonstrated an appropriate basis to support the expert's opinion. The opinion must be grounded on the factors set forth in Section 703, Bases of Opinion Testimony by Experts, namely (a) facts observed by the witness or otherwise in the witness's direct personal knowledge; (b) evidence already in the record or that the parties represent will be presented during the course of the proceedings, which facts may be assumed to be true in questions put to the witness; and (c) facts or data not in evidence if the facts or data are independently admissible in evidence and are a permissible basis for an expert to consider in formulating an opinion. Commonwealth v. Hinds, 487 Mass. 212, 218-221 (2021) (judge must make preliminary determination under Mass. G. Evid. § 104[a] that proponent of expert testimony has established that testimony is based on facts or data reasonably relied on by experts to form opinions in the relevant field); Department of Youth Servs. v. A Juvenile, 398 Mass. 516, 532 (1986) ("If a party believes that an expert is basing an opinion on inadmissible facts or data, the party may request a voir dire to determine the basis of the expert opinion. If the facts or data are admissible and of the sort that experts in that specialty reasonably rely on in forming their opinions, then the expert may state that opinion without the facts or data being admitted into evidence."). See Commonwealth v. Rintala, 488 Mass. 421, 427-429 (2021) (medical examiner properly relied upon information provided by first responders in opining on time of death).
Fourth Foundation Requirement: Reliability of Principle or Method Used by the Expert. Both the United States Supreme Court, applying Fed. R. Evid. 702 in Daubert v. Merrell Dow Pharms., Inc., 509 U.S. 579 (1993), and the Supreme Judicial Court applying the common law in Commonwealth v. Lanigan, 419 Mass. 15 (1994), agree on the fundamental requirement that "[i]f the process or theory underlying [an] . . . expert's opinion lacks reliability, that opinion should not reach the trier of fact." Lanigan, 419 Mass. at 26. A conclusory statement that an expert is "trained" in a particular field is insufficient to establish the reliability of the methodology in which the expert claims to be trained. See Commonwealth v. Rintala, 488 Mass. 421, 437 (2021) (assuming Commonwealth's expert on characteristics of drying paint was qualified, testimony should have been excluded because "his experiments . . . were not based on sufficiently reliable methods"); Commonwealth v. Franceschi, 94 Mass. App. Ct. 602, 609-610 (2018) (accident reconstruction expert should not have been permitted to testify that mark on road was "scuff mark" left by shoe where testimony simply stated his conclusion based on his training and experience and did not explain methodology by which conclusion was reached).
General Acceptance. In Massachusetts courts, reliability may be established by general acceptance alone. "[G]eneral acceptance in the relevant community of the theory and process on which an expert's testimony is based, on its own, continues to be sufficient to establish the requisite reliability for admission in Massachusetts courts regardless of other Daubert factors." Commonwealth v. Patterson, 445 Mass. 626, 640 (2005) (latent fingerprint identification theory). See Commonwealth v. Frangipane, 433 Mass. 527, 538 (2001) ( Lanigan hearing not necessary where qualified expert testimony has been accepted as reliable in the past in Massachusetts appellate cases). In making the general acceptance determination,
"[a] relevant scientific community must be defined broadly enough to include a sufficiently broad sample of scientists so that the possibility of disagreement exists, . . . and . . . trial judges [must] not . . . define the relevant scientific community so narrowly that the expert's opinion will inevitably be considered generally accepted. In the context of technical forensic evidence, the community must be sufficiently broad to permit the potential for dissent."
Patterson, 445 Mass. at 643, quoting Canavan's Case, 432 Mass. 304, 314 n.6 (2000).
If a theory or methodology has been firmly established as reliable in the past, the judge may take judicial notice of its reliability. Commonwealth v. Davis, 487 Mass. 448, 454-455 (2021). However, past acceptance does not establish the reliability of any particular theory or method "for all time, especially in areas where knowledge is evolving and new understandings may be expected as more studies and tests are conducted." Commonwealth v. Shanley, 455 Mass. 752, 763 n.15 (2010). If new scientific knowledge is developed, a Daubert - Lanigan hearing may be necessary to test the continuing validity of a generally accepted theory. Davis, 487 Mass. at 455.
Daubert-Lanigan Analysis. "Where general acceptance is not established by the party offering the expert testimony, a full Daubert analysis provides an alternate method of establishing reliability." Patterson, 445 Mass. at 641. "[W]hen proposed expert testimony uses a new theory, or new methodology to apply an accepted theory, the proponent must establish its reliability using a Daubert - Lanigan analysis." Davis, 487 Mass. at 455. Thus, in Davis, where the Commonwealth sought to use GPS technology to show speed rather than simply location, the trial judge erred in admitting the evidence without proper foundation as to reliability. Id. at 456. See Commonwealth v. Camblin, 471 Mass. 639, 650 (2015) (despite statutory authorization, where evidence offered from breathalyzer machine utilizing new methodology not previously shown to be reliable, Lanigan hearing was required); Patterson, 445 Mass. at 645 (new fingerprint analysis technique).
The five nonexclusive factors established in Daubert are "whether the scientific theory or process (1) has been generally accepted in the relevant scientific community; (2) has been, or can be, subjected to testing; (3) has been subjected to peer review and publication; (4) has an unacceptably high known or potential rate of error; and (5) is governed by recognized standards." Davis, 487 Mass. at 454, quoting Commonwealth v. Powell, 450 Mass. 229, 238 (2007). The Daubert - Lanigan inquiry does not end once it is determined that an expert's methodology is generally accepted. See Lightlab Imaging, Inc. v. Axsun Techs., Inc., 469 Mass. 181, 189-190 (2014) (judge did not abuse discretion in excluding plaintiff's expert testimony on lost profits where expert used generally accepted "discounted cash flow" method, but judge found that expert's application of "first mover advantage" principle was novel application incapable of being validated and tested).
In performing the Daubert - Lanigan analysis, judges may look to their own "own common sense, as well as the depth and quality of the proffered expert's education, training, experience, and appearance in other courts to determine reliability" (quotation and citation omitted). Commonwealth v. Pasteur, 66 Mass. App. Ct. 812, 826 (2006). See Commonwealth v. Shanley, 455 Mass. 752, 766 (2010) ("[T]he judge's finding that the lack of scientific testing did not make unreliable the theory that an individual may experience dissociative amnesia was supported in the record, not only by expert testimony but by a wide collection of clinical observations and a survey of academic literature."). See also Powell, 450 Mass. at 239 (holding court may consider appellate decision from different jurisdiction).
A party offering expert testimony based on personal observations and clinical experience, such as those of a medical expert concerning diagnosis and causation, must show that the testimony is based on reliable principles or methodologies; however, "[i]f the proponent can show that the method of personal observation is either generally accepted by the relevant scientific community or otherwise reliable to support a scientific conclusion relevant to the case, such expert testimony is admissible." Canavan's Case, 432 Mass. 304, 313-314 (2000).
Although the use of the Daubert - Lanigan factors is appropriate for cases involving both the "hard" and "soft" sciences, the analysis may be somewhat different. "The soft sciences are not entitled to less consideration than their hard science counterparts, but the methodologies of each do differ," and accordingly "application of the Daubert - Lanigan standard to soft sciences requires flexibility with special attention being paid to the criteria of reliability that different disciplines develop." Commonwealth v. Hinds, 487 Mass. 212, 221-222 (2021) (holding that exclusion of cultural anthropologist who studies white nationalist movements from testifying as expert that victim's tattoo was affiliated with white supremacist group to support defendant's defense that victim had racially targeted him amounted to prejudicial error). "In other words, not all of the factors identified in Daubert - Lanigan will be applicable in every case" (quotation and citation omitted). Id. at 222. The trial judge's role is to determine the reliability of the expert's methodology and not the persuasiveness of the expert's conclusion. Id. at 224.
The requirements of Lanigan, as amplified in Canavan's Case, do not apply fully as to the standard of care in a medical negligence case. Palandjian v. Foster, 446 Mass. 100, 108-109 (2006) ("How physicians practice medicine is a fact, not an opinion derived from data or other scientific inquiry by employing a recognized methodology. However, when the proponent of expert testimony incorporates scientific fact into a statement concerning the standard of care, that science may be the subject of a Daubert - Lanigan inquiry." [Quotation and citation omitted.]).
Fifth Foundation Requirement: Reliability of the Application of the Principle or Method to the Specific Facts of the Case. Even if an expert's methodology is reliable, it must be reliably applied to the facts of the case. See Lightlab Imaging, Inc. v. Axsun Techs., Inc., 469 Mass. 181, 191-194 (2014) (judge did not abuse her discretion in excluding expert's estimate of lost profits as "too speculative and conjectural as a matter of law"); Commonwealth v. Colturi, 448 Mass. 809, 815-817 (2007) (suggesting that results of breathalyzer test administered more than three hours after offense would not be admissible to establish blood alcohol level at time of offense without expert witness testimony on theory of retrograde extrapolation); Commonwealth v. Talbot, 444 Mass. 586, 589 (2005) (no error in excluding defense expert who was proffered to testify about effects of hypoglycemic shock in view of absence of any evidence that defendant experienced such a condition at time of offense); Commonwealth v. Laliberty, 373 Mass. 238, 241 (1977) (opinion concerning defense of lack of criminal responsibility not admissible absent evidence that defendant suffered from mental disease or defect at time of crime); Smith v. Bell Atlantic, 63 Mass. App. Ct. 702, 718-719 (2005) (even though expert witness was qualified and employed reliable diagnostic method, her lack of knowledge of details of patient's life called into question reliability of her opinion and justified its exclusion in judge's discretion). Cf. Commonwealth v. McNickles, 434 Mass. 839, 847-850 (2001) (disagreement among experts regarding reliability of application of statistical method known as "likelihood ratios" to mixed samples of DNA evidence went to weight, but not admissibility, of expert witness evidence); Fourth St. Pub, Inc. v. National Union Fire Ins. Co., 28 Mass. App. Ct. 157, 161-163 (1989) (It was an abuse of discretion to exclude expert testimony based on a reasonably adequate, albeit incomplete, investigation. "The relevant distinction is between an opinion based upon speculation and one adequately grounded in facts.... [The incompleteness of the investigation] affect[ed] the weight or credibility of the opinion and not its admissibility.").
Duty to Consult with Expert. Where scientific evidence is central to the defense in a criminal case, counsel may have a duty to consult with an appropriate expert. See Commonwealth v. Field, 477 Mass. 553, 556-558 (2017) (error for counsel not to consult with mental health expert regarding defense of mental impairment, but error not likely to have affected verdict). Where science critical to a defense is evolving with new research findings, it may be manifestly unreasonable and present a substantial risk of a miscarriage of justice for counsel to fail to consult or present an expert who could offer evidence in support of the defense. See Commonwealth v. Epps, 474 Mass. 743 (2016) (ineffective assistance of counsel requiring new trial where counsel failed to consult or present expert on possibility of accidental fall as substantial defense in prosecution based upon shaken baby syndrome); Commonwealth v. Millien, 474 Mass. 417 (2016) (failure to consult or call expert on science of shaken baby syndrome). Cf. Commonwealth v. Ayala, 481 Mass. 46, 64 n.20 (2018) (no duty to consult expert in eyewitness identification at time of 2009 trial, when "retention of experts on eyewitness identification was not as prevalent as it is today").
Profile Evidence. Impermissible "[p]rofile evidence focuses on the characteristics of criminals, while proper expert testimony focuses on the characteristics of crimes." Commonwealth v. Barrett, 97 Mass. App. Ct. 437, 444 (2020). Profile evidence used to suggest that a defendant committed an act by comparing the defendant to stereotypes is not relevant and is inherently prejudicial. Commonwealth v. Day, 409 Mass. 719, 723 (1991) (testimony that defendant fit "child battering" profile inadmissible). Similarly, it is inadmissible for an expert to provide so-called negative profile evidence by testifying that the defendant does not match a particular profile. Commonwealth v. Horne, 476 Mass. 222, 227-228 (2017) (testimony that defendant did not fit description of drug addict and so possessed drugs for purposes of distribution is inadmissible).
Cross-Reference: Section 404(a), Character Evidence; Crimes or Other Acts: Character Evidence.
Certitude of Expert Witness Opinion. Generally, an expert's opinion need not be expressed with any specific level of certitude. Commonwealth v. Ronchi, 491 Mass. 284, 302 (2023). However, in Commonwealth v. Heang, 458 Mass. 827 (2011), the Supreme Judicial Court explained that when an expert witness offers an opinion that is empirically based but subjective in nature, such as whether a cartridge or casing was fired from a particular firearm, it is not permissible for the witness to imply that the opinion has a statistical or mathematical basis. "Phrases that could give the jury an impression of greater certainty, such as 'practical impossibility' and 'absolute certainty' should be avoided. The phrase 'reasonable degree of scientific certainty' should also be avoided because it suggests that forensic ballistics is a science, where it is clearly as much an art as a science." (Citation and footnote omitted.) Id. at 849. In Heang, the Supreme Judicial Court provided the following examples of the degree of certitude that an expert witness may express when the opinion is empirically based but subjective in nature: for firearm or ballistics identification, a "reasonable degree of ballistics certainty," Id. at 848-849; for medical examiner and pathologist opinions, a "reasonable degree of medical certainty," Id. at 849, citing Commonwealth v. Nardi, 452 Mass. 379, 383 (2008); Commonwealth v. DelValle, 443 Mass. 782, 788 (2005); for clinical diagnoses, a "reasonable degree of scientific certainty," Commonwealth v. Roberio, 428 Mass. 278, 280 (1998); and for psychological opinions, a "reasonable degree of psychological certainty," Commonwealth v. Wentworth, 53 Mass. App. Ct. 82, 86 (2001). It may also be error for a fingerprint expert to state with absolute certainty that a particular latent print matches a known fingerprint. Commonwealth v. Gambora, 457 Mass. 715, 727-728 (2010). In Heang, the court also noted that there are forensic disciplines that permit expert witness opinion to be expressed to a mathematical or statistical certainty. Heang, 458 Mass. at 849, citing Commonwealth v. Mattei, 455 Mass. 840, 850-853 (2010) (because it is possible to say to mathematical degrees of statistical certainty that one DNA profile matches another, test results and opinions regarding DNA profile must be accompanied by testimony explaining likelihood of that match occurring in general population). In Ronchi, 491 Mass. at 303, the court declined to extend the Heang decision to require that all experts testify to a reasonable degree of certainty.
Illustrations.
Abused Children. See Commonwealth v. Federico, 425 Mass. 844, 847-848 (1997).
Automobile Damage. See Laccetti v. Ellis, 102 Mass. App. Ct. 416, 420-422 (2023) (photographs of damage to vehicles involved in collision relevant to likelihood and degree of personal injury, even without expert testimony).
Battered Woman Syndrome. The defendant has a statutory right under G. L. c. 233, § 23F, to present such evidence "where certain specified defenses are asserted." Commonwealth v. Asenjo, 477 Mass. 599, 607-609 (2017) ("Section 23F is more permissive than the common law bases for expert opinions outlined in Mass. G. Evid. § 703.").
Bloodstain Analysis. See Commonwealth v. Vasquez, 462 Mass. 827, 844-846 (2012); Commonwealth v. Powell, 450 Mass. 229, 237-241 (2007).
Breath Test Analysis. See Commonwealth v. Camblin, 478 Mass. 469, 480 (2017).
Capacity to Contract. See Sparrow v. Demonico, 461 Mass. 322, 327-330 (2012).
Cause and Origin of Fire. See Commonwealth v. Rosario, 477 Mass. 69, 80-81 (2017); Commonwealth v. Goodman, 54 Mass. App. Ct. 385, 389-393 (2002).
Computer Simulations. Evidence consisting of computer-generated models or simulations is treated like other scientific tests; admissibility is conditioned "on a sufficient showing that: (1) the computer is functioning properly; (2) the input and underlying equations are sufficiently complete and accurate (and disclosed to the opposing party, so that they may challenge them); and (3) the program is generally accepted by the appropriate community of scientists." Commercial Union Ins. Co. v. Boston Edison Co., 412 Mass. 545, 549-550 (1992). See also Grand Manor Condominium Ass'n v. City of Lowell, 100 Mass. App. Ct. 765, 769-770 (2022) (three-dimensional model created using computer software program admissible because software had general acceptance in relevant community and model was an aid to expert testimony).
Contribution of Alcohol to Personal Injury. See Baudanza v. Comcast of Mass. I, Inc., 454 Mass. 622, 631-633 (2009).
Coprophilia (Sexual Fetish). See Commonwealth v. Lawton, 82 Mass. App. Ct. 528, 538-539 (2012).
Development of Adolescent Brain. General expert testimony on adolescent brain development concerning whether people in the defendant's age group can form the requisite intent for murder is not relevant unless accompanied by evidence pertaining to the particular defendant. Commonwealth v. Ridley, 491 Mass. 321, 328 (2023); Commonwealth v. Fernandes, 487 Mass. 770, 782-783 (2021). Importantly, "evidence of juvenile brain development" is treated "differently from evidence about the effects of intoxicating substances, where generalized expert testimony is permitted." Fernandes, 487 Mass. at 782.
Dissociative Memory Loss. See Commonwealth v. Polk, 462 Mass. 23, 32-36 (2012).
Dissociative Trance Disorder. See Commonwealth v. Montanez, 55 Mass. App. Ct. 132, 144-146 (2002).
Distributing Heroin. See Commonwealth v. Miranda, 441 Mass. 783, 792-795 (2004).
DNA. See Commonwealth v. Dixon, 458 Mass. 446, 453 (2010) ("[a] properly generated DNA profile is a string of code that exclusively identifies a person's hereditary composition with near infallibility"); Commonwealth v. Mattei, 455 Mass. 840, 847-852 (2010) (evidence that DNA test failed to exclude defendant "without accompanying evidence that properly interprets that result creates a greater risk of misleading the jury and unfairly prejudicing the defendant than admission of a 'match' without accompanying statistics"). There is a distinction between nonexclusion (the defendant is not excluded as a contributor of the sample) and inconclusive (insufficient sample material, contamination, or some other problem) DNA results. "Evidence that a defendant is not excluded could suggest to the jury that a link would be more firmly established if only more [sample] were available for testing. Such evidence should not [be] admitted without accompanying statistical explanation of the meaning of nonexclusion." Commonwealth v. Cameron, 473 Mass. 100, 106 (2015). See Commonwealth v. Seesangrit, 99 Mass. App. Ct. 83, 91 (2021) (expert testimony sufficient to support DNA evidence when expert testified that "sample was sufficient to exclude 99.7% of DNA profiles of Asian males in the United States, but that the defendant's DNA profile could not be excluded"). See also Commonwealth v. Lester, 486 Mass. 239, 247 (2020) (admission of DNA charts not error but "the better course is to remind the jury that they must consider the charts in conjunction with the expert's testimony, including the expert's statistical analysis"). Inconclusive DNA results are not relevant absent a Bowden defense. Cameron, 473 Mass. at 107 n.8. See Section 1107, Inadequate Police Investigation Evidence.
Effect of Intoxicants. See Commonwealth v. Sherman, 481 Mass. 464, 477-478 (2019) (evidence of drug use to challenge witness's ability to perceive and remember must be supported by expert testimony where connection between drug use and witness's ability to perceive, remember, or testify to event is not generally known). See also Commonwealth v. Hernandez, 481 Mass. 189, 194 (2019) (question put to lay witness concerning how a person reacts to heroin withdrawal improper because it required specialized knowledge).
Estimated Time of Death. See Commonwealth v. Rintala, 488 Mass. 421, 427-429 (2021).
Extrapolation. Extrapolation evidence to determine the weight of drugs is permissible, and any objections to its admissibility should be raised by way of pretrial motion. Commonwealth v. Crapps, 84 Mass. App. Ct. 442, 445-449 (2013).
False Confessions. See Commonwealth v. Hoose, 467 Mass. 395, 413-420 (2014); Commonwealth v. Conley, 103 Mass. App. Ct. 496, 501-503 (2023) (proffered expert testimony on voluntary false confessions to protect another properly excluded where no studies focused on this type of false confession, expert had no information or opinion on its prevalence, and no relevant discipline had established any reliability criteria for opinion).
Field Testing Drugs. See Commonwealth v. Fernandez, 458 Mass. 137, 151 (2010); Commonwealth v. Rodriguez, 92 Mass. App. Ct. 774, 779-780 (2018).
Fingerprints. See Commonwealth v. Patterson, 445 Mass. 626, 641-655 (2005). See also Commonwealth v. Joyner, 467 Mass. 176, 177 (2014) (testimony of fingerprint expert did not violate prohibition against expressing an opinion to a scientific certainty that there was a match). Where a fingerprint is the only identification evidence, the Commonwealth must prove beyond a reasonable doubt that the fingerprint was placed during the commission of the charged crime. Commonwealth v. French, 476 Mass. 1023, 1024-1025 (2017). Unlike DNA evidence, the statistical significance of an opinion about a match is not a foundational requirement but may affect the weight of the evidence. Commonwealth v. Wadlington, 467 Mass. 192 (2014). Cf. Commonwealth v. Gambora, 457 Mass. 715, 724-725 (2010) (considering report by National Research Council, Strengthening Forensic Science in the United States: A Path Forward 102-104, 136-145 [2009]). It is not enough for an expert to avoid testifying that the match is 100 percent certain; the Commonwealth has an affirmative duty to elicit on direct examination the expert's testimony that the match is an opinion based on the expert's education, training, and experience. Commonwealth v. Robertson, 489 Mass. 226, 238 (2022) (suggesting prosecutors ask whether witness has an opinion "to a reasonable degree of fingerprint analysis certainty").
Firearm Identification (Forensic Ballistics). See Commonwealth v. Heang, 458 Mass. 827, 847-848 (2011) (adopting "guidelines" for the admissibility of expert firearm identification testimony that [1] require documentation of the basis of the expert's opinion before trial, which the Commonwealth must disclose to the defense in discovery; [2] require an explanation by the expert to the jury of the theories and methodologies underlying the field of forensic ballistics before offering any opinions; and [3] limit the degree of certitude that the qualified expert may express about whether a particular firearm fired a specific projectile or cartridge to a "reasonable degree of ballistic certainty").
Gang Membership. See Commonwealth v. Henley, 488 Mass. 95, 127-128 (2021) (meaning of common gang terminology); Commonwealth v. Barbosa, 477 Mass. 658, 667-669 (2017).
Global Positioning System (GPS). See Commonwealth v. Davis, 487 Mass. 448, 455-459 (2021).
Gunshot Residue. See Commonwealth v. Johnson, 463 Mass. 95, 107-108 (2012); Commonwealth v. Heang, 458 Mass. 827, 851 (2011).
Hair Comparison Analysis. An expert's testimony on the probability of a particular inclusion of a person as a source of a hair of unknown origin cannot be scientifically supported. Commonwealth v. Eagles, 491 Mass. 210, 215-216 (2023).
Personality Testing. See Ready, petitioner, 63 Mass. App. Ct. 171, 172-179 (2005).
Posttraumatic Stress Disorder. See Commonwealth v. Anestal, 463 Mass. 655, 658 n.5 (2012); Commonwealth v. Crawford, 429 Mass. 60, 67 (1999).
Retrograde Extrapolation. See Commonwealth v. Senior, 433 Mass. 453, 458-462 (2001). But see Commonwealth v. Dacosta, 85 Mass. App. Ct. 386, 386-388 (2014) (breath test within fifty minutes of arrest permits inference of blood alcohol content above 0.08 percent without need for expert witness testimony).
Sex Offender, Failure to Register. See Commonwealth v. Corbett, 101 Mass. App. Ct. 355, 362-364 (2022) (because crime of failure to register as sex offender requires proof that defendant "knowingly" failed to register, judge erroneously excluded defendant's proffered expert testimony regarding his mental state).
Sex Offender Registry Board. See John Doe, Sex Offender Registry Bd. No. 234076 v. Sex Offender Registry Bd., 484 Mass. 666, 673-674 (2020) (expert testimony admissible in classification hearings unless it is irrelevant, unreliable, or repetitive).
Sexual Assault Evidence. See Commonwealth v. Scesny, 472 Mass. 185, 194-196 (2015), abrogated on other grounds by Commonwealth v. Paige, 488 Mass. 677, 680-681 (2021) (testimony regarding what evidence criminologist would expect to have found if victim pulled up her underwear and pants following intercourse).
Sexually Dangerous Persons. See Commonwealth v. George, 477 Mass. 331, 341-342 (2017) (Static-99R risk assessment tool's raw score and risk percentage are admissible; Static-99R risk category labels are inadmissible, as they do not provide sincere, numeric estimates of recidivism risk); Commonwealth v. Ortiz, 93 Mass. App. Ct. 381, 389 (2018) (no abuse of discretion in excluding penile plethysmograph [PPG] examination results on issue of likelihood of sexual reoffense).
Shaken Baby Syndrome. See Commonwealth v. Epps, 474 Mass. 743 (2016); Commonwealth v. Millien, 474 Mass. 417 (2016).
Susceptibility to Suggestiveness. See Commonwealth v. Soares, 51 Mass. App. Ct. 273, 280-282 (2001).
Valuation of Business Interest. In divorce cases, the judge may accept one expert valuation over another or reject expert opinion altogether and arrive at a valuation on other evidence but may not reach a valuation that varies from the requirements of the equitable distribution statute. G. L. c. 208, § 34. See Adams v. Adams, 459 Mass. 361, 380-381 (2011); Bernier v. Bernier, 449 Mass. 774 (2007).
Valuation of Real Estate. There is no requirement that the person testifying as an expert have sales or practical experience in the locality about which they are testifying. See McLaughlin v. Board of Selectman of Amherst, 422 Mass. 359, 362-363 (1996). A real estate broker or appraiser with "sufficient experience and knowledge of values of other similar real estate in the particular locality" may testify. Lee Lime Corp. v. Massachusetts Turnpike Auth., 337 Mass. 433, 436 (1958). A witness who had "worked as an appraiser" and "was in the process of earning professional designations in the appraisal field" may testify as an expert in real estate. See Lavin v. Lavin, 24 Mass. App. Ct. 929, 931 (1987). An expert witness may use the depreciated reproduction cost method to form an opinion as to the value of real estate when the judge finds that there is a justification for the use of this disfavored approach. Correia v. New Bedford Redev. Auth., 375 Mass. 360, 362-367 (1978).
For examples of cases applying this section, see M.S. Brodin & M. Avery, Massachusetts Evidence §§ 7.4-7.6 (2018 ed.); 2 M.G. Perlin & D. Cooper, Proof of Cases in Massachusetts §§ 71:1-71:23 (2017-2018 ed.); and W.G. Young, J.R. Pollets, & C. Poreda, Annotated Guide to Massachusetts Evidence § 702 (2017-2018 ed.).
Jury Instructions. See Commonwealth v. Hinds, 450 Mass. 1, 12 n.7 (2007).
Section 703, Bases of Opinion Testimony by Experts.