By Derek Stikeleather

I.               Introduction

In the first three years after its landmark decision in Rochkind v. Stevenson, the Supreme Court of Maryland handed down four decisions construing the Daubert/Rochkind standard[1] for admissibility of expert testimony, specifically whether an expert’s challenged opinion had a sufficient factual basis under subsection 3 of Maryland Rule 5-702.[2] Each case addressed whether the challenged trial court’s opinion had an impermissible analytical gap between the expert’s methodology and conclusion.[3] A surprising trend is the relatively high number of appellate reversals for abuse of discretion by the trial court, and the frequent disagreements among the appellate courts—even the judges themselves—on how to apply the abuse of discretion standard. Despite the familiar mantra that “it is still the rare case in which a Maryland trial court’s exercise of discretion to admit or deny expert testimony will be overturned,”[4] it has not seemed rare at all—at least so far.[5]

Maryland Supreme Court Opinions	Trial court: Is opinion admissible under Rule 5-702(3)?	Appellate Court: Did trial judge abuse discretion?	Supreme Court: Did trial judge abuse discretion?
Katz Abosch (Aug. 2023)	No, remand, then No	Yes	Maybe, remand, then No
Oglesby (July 2023)	No	No	Yes (7-0)
Abruquah (June 2023)	Yes	Bypass petition	Yes (4-3)
Matthews (2022)	Yes	Yes	No (6-1)

Figure 1[6]

II.             Daubert Litigation

A.    State v. Matthews

The Matthews case involved the FBI’s use of a technique called “reverse projection photogrammetry” to determine a person’s height from a photograph or surveillance image.[7] Minutes after a late-night murder, surveillance video captured images of a man with an indiscernible face walking away from the murder scene and carrying an apparent shotgun—the murder weapon.[8] At Mr. Matthews’s murder trial, an FBI expert took the stand and used a still-frame image from the video to estimate the man’s height at 5’8” with an 0.67” plus/minus.[9] That same witness had earlier conceded a three-inch plus/minus, that she could not see.[10] The Appellate Court of Maryland held that this created too much uncertainty to be helpful to the jury’s deliberation and, instead, offered speculative, misleading expert testimony.[11] Applying the abuse of discretion standard, the appellate court rejected the testimony as inadmissible as a matter of law.[12]

The Supreme Court of Maryland saw Matthews differently, characterizing the testimony as not inadmissible per se because the underlying technique was reliable and the FBI expert conceded the uncertainties in her case-specific opinion.[13] The Court emphasized that there was “no dispute in this case concerning the reliability of [the expert’s] methodology,” reverse projection photogrammetry.[14] Because the expert “explained on direct examination that several other factors, including the unevenness of the ground and the distance of the camera from the subject, could add to the degree of uncertainty in a way she could not calculate,” the trial court had the discretion to allow it—or presumably, to exclude it.[15]

The Court distinguished the “uncertainty inherent in an expert’s methodology and uncertainty that applies to an expert’s conclusions following the application of a reliable methodology.”[16] An unreliable methodology would produce an inadmissible conclusion virtually every time; nevertheless, an opinion “is generally less problematic” when an expert applies a reliable technique “to an adequate supply of data, but in reporting her results, states that she is unable to quantify a specific degree of uncertainty/margin of error.”[17]

B.    Abruquah v. State

The Supreme Court of Maryland’s Abruquah decision presented the inverse of the Matthews situation.[18] The Court held that firearms-identification testimony admitted by the trial court, based on a well-established and rigorous methodology, was inadmissible as a matter of law because of the high degree of certainty that the expert expressed to jurors.[19] At trial, the State’s expert firearms examiner testified that a bullet from the scene not only matched sample bullets fired from defendant Mr. Abruquah’s gun but also had been fired from his gun.[20]

For the Court’s narrow 4-3 Majority, that expert testimony was too much.[21] The Court concluded that “the examiner should not have been permitted to offer the unqualified opinion that the crime scene bullets were fired from Mr. Abruquah’s gun.”[22] It reasoned that the firearms-identification methodology can reliably show a bullet’s consistency with a specific gun but not an “unqualified conclusion that such bullets were fired from a particular firearm.”[23]  Thus, the expert could have told jurors that he believed that the bullet probably came from the defendant’s gun. He even might have been allowed to testify that the bullet almost certainly came from the defendant’s gun. However, the unqualified testimony that the bullet was from the defendant’s gun was inadmissible.[24]

To the dissenting Justices, such thin slicing of the admissibility of opinion testimony seemed incompatible with Rochkind’s deferential abuse of discretion standard of review.[25] The Majority recognized that a reviewing court should not reverse simply because it would not have made the same ruling, and that there is an abuse of discretion when admitting “expert evidence where there is an analytical gap between the type of evidence the methodology can reliably support and the evidence offered.”[26] Nevertheless, the dissenting Justices struggled to see the Majority’s opinion as anything other than reversal simply because the appellate judges would not have made the same ruling as the trial judge.[27]

Seeming only to affirm the dissenting Justices’ criticisms, footnote 5 in the Abruquah Majority opinion described the traditional articulation of the abuse of discretion standard as “somewhat unfair” without changing the standard:

This Court has frequently described an abuse of discretion as occurring when “no reasonable person would take the view adopted by the circuit court” or when a decision is “well removed from any center mark imagined by the reviewing court and beyond the fringe of what the court deems minimally acceptable.” [citations] In our view, the application of those descriptions to a trial court’s application of a newly adopted standard, such as that adopted by the Rochkind Court as applicable to the admissibility of expert testimony, is somewhat unfair. In this case, in the absence of additional case law from this Court implementing the newly adopted standard, the circuit court acted deliberately and thoughtfully in approaching, analyzing, and resolving the question before it. This Court’s majority has come to a different conclusion concerning the outer bounds of what is acceptable expert evidence in this area.[28]

Footnote 5’s juxtaposition of the apparently unfair “beyond the fringe of what the court deems minimally acceptable” with the apparently fair “outer bounds of what is acceptable” plays with semantics and tone but does not change the standard.[29] Requiring expert testimony to be “acceptable” or “minimally acceptable” is synonymous.[30] Likewise, there is no difference between requiring testimony not to exceed “the fringe” of acceptability as opposed to the “outer bounds” of acceptability.[31] While footnote 5 shows some unease, it does not change the abuse of discretion standard in any meaningful way.[32]

More startling was the Majority’s holding that the trial court had to decide admissibility “in the absence of additional case law from this Court implementing the newly adopted standard.”[33] While Daubert was “newly adopted” in Maryland and “this Court” has not created a large body of Daubert case law, Daubert preceded Abruquah by three decades.[34] There is a plethora of Daubert case law to guide trial courts, including cases on firearms-identification testimony.[35]

The Majority’s decision thus invites confusion. The wisdom of adopting Daubert under Rochkind and ending two decades of “jurisprudential drift” was the legal clarity that it provided in the already complex and nuanced world of assessing the reliability and admissibility of expert testimony.[36] The Rochkind decision did not wipe the slate clean for a new generation of Maryland judges to re-invent Rule 5-702.[37] Rather, adopting Daubert gave Maryland a tried-and-true approach to expert admissibility that saves trial judges from having to make these important decisions “in the absence of additional caselaw.”[38] Fortunately, subsequent decisions applying Rochkind have returned to long-accepted articulations of the abuse of discretion standard,[39] thereby leaving Abruquah alone on its facts to create a rule against unqualified firearms.[40]

C.    Oglesby v. Baltimore Schools Associates

While the Supreme Court of Maryland’s Abruquah decision narrowly found admitted testimony inadmissible as a matter of law,[41] the Oglesby decision unanimously found excluded testimony admissible as a matter of law.[42] There, the Court reversed the trial court’s exclusion of expert testimony that lead-paint exposure at the defendant’s property caused the plaintiff’s injuries, including IQ loss.[43] In doing so, it also reversed the appellate court’s decision that the trial court had acted within its broad discretion to exclude the opinions.[44] The unanimous Court held not only that the trial court had erroneously applied Rule 5-702 but that the excluded causation opinions—except those on IQ loss—were admissible as a matter of law.[45] It remanded for the trial court to decide admissibility of the IQ-loss opinions under correct application of Rule 5-702.[46]

For the Oglesby Court, the fundamental problem with the trial court’s exclusion of expert testimony was its impermissible resolution of several disputed facts that supported the expert’s opinion.[47] The problem was especially glaring because the trial court stated that it was resolving disputed factual issues that “normally could be presented to a jury.”[48] The Court found that the trial court “did not explain what it meant, [or] identify what the incorrect information” and factual issues were.[49] The Court also emphasized that experts can rely on disputed facts that have a sufficient factual basis.[50] Further, although disputed, “there was more than an adequate supply of data and information” to support the excluded opinions.[51]

D.   Katz, Abosch, Windesheim, Gershman & Freedman, P.A. v. Parkway Neuroscience & Spine Inst., LLC. (KatzAbosch)

The prior opinions set the stage for the Supreme Court of Maryland’s August 2023 KatzAbosch decision, where the Court addressed, for the third time in three months, the appropriate level of deference that appellate courts must show to trial judges making Rule 5-702 Rochkind decisions.[52] While the trial court had excluded the expert, the Appellate Court of Maryland reversed, finding the excluded opinions admissible as a matter of law.[53] The Supreme Court of Maryland vacated the appellate court’s decision and, while retaining its jurisdiction, remanded to the trial court to analyze admissibility without considering one of the factors it had originally weighed.[54] In doing so, it emphasized that the “case centers on the primacy—and boundaries—of methodological reliability in the Daubert-Rochkind analysis.”[55] A year later, after the trial court excluded the opinions again, the Court affirmed the exclusion.[56]

The KatzAbosch case involved a medical practice’s allegations of accounting malpractice that purportedly prompted a mass exodus of its members.[57] The medical practice proffered an accounting expert to use “the widely accepted ‘before-and-after’ method to” support its lost-profits claim.[58] While the trial court properly rejected the expert’s inputs as unreliable under Rochkind, its critique of the experts’ normalizing adjustments was improper, requiring the trial court to explain whether the opinions remained inadmissible without considering the normalizing adjustments.[59]

The KatzAbosch Court focused on the line that separates an expert’s reviewable methodology from the expert’s presumably unreviewable data.[60] It rejected a rigid approach, holding that “whether an expert’s methodology is sufficiently reliable to admit the expert’s testimony at trial will sometimes require a trial court to consider data and assumptions that the expert has employed in deciding threshold points relating to the methodology.”[61]

KatzAbosch also revealed an emerging pattern of judicial uncertainty in post-Rochkind decisions both applying Rule 5-702 at trial and in reviewing such decision for abuse of discretion. The Supreme Court of Maryland had reversed three decisions by the Appellate Court of Maryland applying the abuse of discretion standard, only doing so unanimously once.[62] This prompted Justice Booth to draft a concurrence, joined by Justice Gould, in KatzAbosch.[63] Within, Justice Booth suggested that the Court “reformulate the definition of our abuse of discretion standard in the context of appellate review of expert witness testimony admissibility determinations.”[64]

Justice Booth did not suggest departing from abuse of discretion, rather articulating “an abuse of discretion standard that is in line with the federal courts’ formulation and that reflects this Court’s current practice.”[65] She explained that, by adopting the Daubert standard “in full,” Maryland necessarily adopted “the federal courts’ application of the abuse of discretion standard.”[66]

The concurrence explained that Maryland has used the common formulation that “an abuse of discretion occurs when no reasonable person would take the view adopted by the circuit court or when a decision is well removed from any center mark imagined by the reviewing court and beyond the fringe of what the court deems minimally acceptable.”[67] However, the concurrence also argued that the deferential standard is context-sensitive.[68] An abuse of discretion review under Daubert “involves a more searching and careful examination of the records, data, studies, testimony, and trial court’s analysis of the same.”[69] After presenting several federal circuits’ articulation of the relevant standards, the concurrence concludes with its own proposed standard of review for Rule 5-702 rulings.[70] It urges the Court to clarify that a trial court abuses its discretion when it (1) applies the wrong law, (2) follows the wrong procedure, (3) bases its decision on clearly erroneous facts, (4) commits a clear error of judgment, or (5) abdicates its gatekeeping role altogether.[71]

III.           Conclusion

Adopting Daubert further clarified Maryland Rule 5-702 by keeping unreliable opinion testimony from jurors. Maryland courts and practitioners must now bear in mind that Rochkind did not wipe the slate clean. Daubert has existed for over thirty years, and federal and state courts nationwide have effectively applied its abuse of discretion standard. Maryland courts are no exception, having applied Daubert principles long before the Rochkind decision.[72] While the Daubert inquiry is often complex and fact-intensive, its gatekeeping role remains central to giving all parties a fair trial in civil and criminal cases.[73]

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Derek Stikeleather chairs the Appellate Practice Group at Goodell DeVries. He practices primarily in appellate advocacy and complex litigation, often as national appellate counsel for clients responding to nuclear verdicts. Derek has vast experience in commercial disputes and defending medical malpractice, product liability, and class action claims. Derek has a robust Maryland practice. He helped the Goodell DeVries team that persuaded the Supreme Court of Maryland, in 2020, to formally adopt the Daubert standard for expert testimony in all state-court civil and criminal proceedings and retire the Frye-Reed test. As an editor of the Maryland Appellate Blog and co-Chair of the MSBA’s Appellate Practice Committee, Derek continues to publish regularly on Maryland courts’ application of the Daubert standard under Rule 5-702. Derek is also a member of the Cole-Davidson Inn of Court, Maryland’s only appellate Inn of Court.Derek’s efforts have earned him a Tier I rating from Chambers USA (its highest rating) for Maryland appellate lawyers. In 2024, Best Lawyers in America named him Baltimore’s Lawyer of the Year for appellate practice.

[1] “The Daubert factors provide guidance on how to determine if scientific reasoning is, indeed, sound, or a scientific theory adequately justifies an expert’s conclusion.” Rochkind v. Stevenson, 471 Md. 1, 33 (2020). In Rochkind, the Supreme Court of Maryland adopted the Daubertfactors to its interpretation of Md. Rule 5-702, thereby eliminating the Frye-Reedstandard and “provid[ing] a simpler, more straightforward analysis of expert testimony.” Id. at 37.

[2] State v. Matthews, 479 Md. 278 (2022); Abruquah v. State, 483 Md. 637 (2023); Oglesby v. Balt. Sch. Assocs., 484 Md. 296 (2023); Katz, Abosch, Windesheim, Gershman & Freedman, P.A. v. Parkway Neuroscience and Spine Institute, LLC, 485 Md. 335 (2023); see discussion infra Part II.

[3] See discussion infra Part II.

[4] Matthews, 479 Md. 278, 306 (first quoting Rochkind v. Stevenson, 471 Md. 1, 10 (2020); and then quoting Roy v. Dackman, 445 Md. 23, 38–39 (2015)).

[5] See Derek Stikeleather, 2023 and the Summer of Daubert, Md. App. Blog tbl.1 (Sept. 7, 2023), https://mdappblog.com/2023/09/07/2023-and-the-summer-of-daubert/.

[6] Id.

[7] Matthews, 479 Md. 278, 285 (internal quotation marks omitted).

[8] Id.

[9] Id.

[10] Id.

[11] Id. at 286, 304–05.

[12] Id. at 304.

[13] Matthews, 479 Md. 278, 314.

[14] Id. at 315.

[15] Id. at 301.

[16] Id. at 315.

[17] Id.

[18] SeeAbruquah v. State, 483 Md. 637, 648 (2023).

[19] Id. at 696–97.

[20] Id. at 696.

[21] See id.; see alsoDerek Stikeleather, Abruquah v. State Debates Abuse of Discretion Under Rule 5-702, Md. App. Blog (June 29, 2023), https://mdappblog.com/2023/06/29/abruquah-v-state-debates-abuse-of-discretion-under-rule-5-702/.

[22] Abruquah, 483 Md. 637, 648.

[23] Id.

[24] Id.

[25] Id. at 652.

[26] Id.

[27] See Abruquah, 483 Md. at 710 (Hotten, J., dissenting).

[28] Id. at 652 n.5.

[29] Id. at 710 (internal quotation marks omitted).

[30] Id. (internal quotation marks omitted).

[31] Id. (internal quotation marks omitted).

[32] Id.

[33] Abruquah, 483 Md. at 652 n.5.

[34] Id.; see generally Daubert v. Merrell Dow Pharm., Inc., 509 U.S. 579 (1993).

[35] See Abruquah, 483 Md. at 713 (Gould, J., dissenting) (“To the contrary, there is no shortage of federal cases applying the Daubert factors[.]”). Likewise, several states have applied the Daubert abuse of discretion standard. E.g., Bunting v. Jamieson, 984 P.2d 467 (Wyo. 1999); Craddock v. Watson, 475 S.E.2d 62 (W. Va 1996); USGen New England, Inc. v. Town of Rockingham, 862 A.2d 269, 271 (Vt. 2004); Utah v. Schultz, 58 P.3d 879 (Ut. 2002); Texas v. Stovall, 140 S.W.3d 712 (Tex. App. 2004); Tennessee v. Stevens, 78 S.W.3d 817 (Tenn. 2002); South Dakota v. Machmuller, 630 N.W.2d 495 (S.D. 2001); DiPetrillo v. Dow Chem. Co., 729 A.2d 677 (R.I. 1999); Christian v. Gray, 65 P.3d 591 (Okla. 2003); Lewis v. Alfa Laval Separation, Inc., 714 N.E.2d 426 (Ohio 1998); Howerton v. Arai Helmet, Ltd., 597 S.E.2d 674 (2004), superseded by statute, N.C. Gen. Stat. Ann. § 8C-1, Rule 702 (West 2025); New Mexico v. Paiz, 149 P.3d 579 (N.M. 2006); New Jersey v. Olenowski, 304 A.3d 598 (N.J. 2023); New Hampshire v. Hungerford, 697 A.2d 916 (N.H. 1997); Nevada v. Repinec, 130 Nev. 1234 (2014); Nebraska v. Hill, 851 N.W.2d 670 (Neb. 2014); Montanna v. Bieber, 170 P.3d 444 (Mont. 2007); Missouri v. Addie, 655 S.W.3d 456 (Mo. Ct. App. 2022); Mississippi Transp. Comm’n v. McLemore, 863 So. 2d 31 (Miss. 2003); Danhoff v. Fahim, 15 N.W.3d 262 (Mich. 2024); Massachusetts v. Davis, 168 N.E.3d 294 (Mass. 2021); Maine v. MacDonald, 718 A.2d 195 (Me. 1998); LaBauve v. Louisiana Med. Mut. Ins. Co., 347 So. 3d 724 (La. 2022); Miller v. Eldridge, 146 S.W.3d 909 (Ky. 2004); Kansas v. Aguirre, 485 P.3d 576 (Kan. 2021); Iowa v. More, 880 N.W.2d 487 (Iowa 2016); Indiana v. West, 755 N.E.2d 173 (Ind. 2001); Idaho v. Trevino, 980 P.2d 552 (Idaho 1999); In re Doe, 981 P.2d 723 (Haw. Ct. App. 1999); Butler v. Union Carbide Corp., 712 S.E.2d 537 (Ga. Ct. App. 2011);  Florida v. Miller, 379 So. 3d 1109, 1122 (Fla. 2024), cert. denied sub nom. Florida v. Miller, 145 S. Ct. 241 (2024); Pettus v. United States, 37 A.3d 213 (D.C. 2012); Gen. Motors Corp. v. Grenier, 981 A.2d 531 (Del. 2009);  Connecticut v. Kirsch, 820 A.2d 236, 244 (Conn. 2003); Smith v. Belle Bonfils Mem’l Blood Ctr., 976 P.2d 344 (Colo. Ct. App. 1998); California v. Johnson, 23 Cal. Rptr. 2d 703 (Cal. Ct. App. 1993), McCullon v. Arkansas, 679 S.W.3d 358 (2023); Logerquist v. McVey, 1 P.3d 113, 124 (Ariz. 2000) ; Alaska v. Sharpe, 435 P.3d 887 (Alaska 2019); Ex parte George, 370 So. 3d 591 (Ala. 2021).

[36] Rochkind v. Stevenson, 471 Md. 1, 26 (2020).

[37] In Rochkind, the Supreme Court of Maryland acknowledged that adopting Daubert did not eliminate considering whether the expert relied upon generally accepted scientific principles:

Frye centered on whether scientific principles or discoveries were generally accepted . . . . Yet, using acceptance as the only measure of reliability presents a conundrum: a generally accepted methodology may produce ‘bad science’ and be admitted, while a methodology not yet accepted may be excluded, even if it produces ‘good science.’ General acceptance remains an important consideration in the reliability analysis, but it cannot remain the sole consideration.

Id. at 30 (citation omitted).

[38] Abruquah, 483 Md. at 712–13 (Gould, J., dissenting).

[39] See, e.g., Oglesby v. Balt. Sch. Assocs., 484 Md. 296 (2023); Katz, Abosch, Windesheim, Gershman & Freedman, P.A., v. Parkway Neuroscience and Spine Institute, LLC., 485 Md. 335 (2023).

[40] See Abruquah, 483 Md. at 696.

[41] Id. at 695.

[42] Oglesby, 484 Md. at 305.

[43] Id. at 305–06.

[44] Id. at 305.

[45] Id. at 361–62.

[46] Id. at 362.

[47] Oglesby, 484 Md. at 304–05.

[48] Id. at 305 (internal quotation marks omitted).

[49] Id. at 331.

[50] Id. at 333.

[51] Id. at 340.

[52] See generallyKatz, Abosch, Windesheim, Gershman & Freedman, P.A. v. Parkway Neuroscience & Spine Inst., LLC., 485 Md. 335 (2023).

[53] Id. at 344.

[54] Id. at 345.

[55] Id. at 368.

[56] Katz, Abosch, Windesheim, Gershman & Freedman, P.A. v. Parkway Neuroscience & Spine Inst., LLC, 487 Md. 632, 635 (2024).

[57] KatzAbosch, 485 Md. at 343.

[58] Id.

[59] Id. at 345.

[60] Id. at 369.

[61] Id. at 376.

[62] KatzAbosch, 485 Md. at 385.

[63] See id. at 385 (Booth, J., concurring) (citing State v. Matthews, 479 Md. 278 (2022); Abruquah v. State, 483 Md. 637 (2023); Oglesby v. Balt. Sch. Assocs., 484 Md. 296 (2023)).

[64] Id.

[65] Id. at 387.

[66] Id.

[67] Id.at 391 (internal quotation marks omitted).

[68] KatzAbosch, 485 Md. at 398.

[69] Id. at 400.

[70] See id. at 401–04 (referencing decisions by the First, Seventh, Tenth, and Eleventh Circuits).

[71] Id. at 406 (internal quotation marks and citations omitted).

[72] See, e.g., Blackwell v. Wyeth, 408 Md. 575 (2009).

[73] See Victor E. Schwartz & Cary Silverman, The Draining of Daubert and the Recidivism of Junk Science in Federal and State Court