Legal malpractice standard-of-care expert
Expert class library · Professional liability · Either side
A lawyer who testifies whether another lawyer's handling of a matter met the standard of care and whether the client would have done better but for the error. Courts generally admit standard of care opinions from experienced practitioners, including opinions that draw on the rules of professional conduct, but strike opinions that a claim is simply without merit and settlement value forecasts that rest on assumed facts.
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What this expert is retained to answer
- Does the expert practice, or has the expert practiced, in the area of law at issue, and does any gap matter for the specific opinions offered?
- Is the expert measuring the lawyer's conduct against a standard of care, or simply stating that the malpractice claim lacks merit?
- How does the expert use the rules of professional conduct: as evidence of the standard of care, or as the standard itself?
- What facts support the opinion that the underlying case would have settled or won, and for how much?
- Did the expert rely on a verdict and settlement compilation, and who assembled it?
Methods
- Case-within-a-case analysis
- Rules of professional conduct comparison
- Litigation file review
- Settlement value analysis
- Verdict and settlement data comparison
How the testimony is attacked
- Settlement value built on assumed facts. Challengers show that a but for opinion on what the underlying case would have settled for rests on facts the record contradicts. In Lavina v. Satin the Massachusetts Superior Court struck a legal expert's causation and settlement value opinion under Daubert and Lanigan while keeping her standard of care opinions.
- Ultimate legal conclusions. Opponents move to strike statements that the claims are unfounded or without merit. In Atlanta Channel, Inc. v. Solomon the District of Columbia federal court struck two such statements as legal conclusions but admitted the rest of the defense expert's standard of care opinions.
- Lack of experience in the field of practice. Defendants argue the expert does not practice in the specialty at issue. In Desimini v. Durkin the District of New Hampshire held that a lack of family law practice went to weight because the defendants did not show the gap disqualified the expert from the specific opinions offered.
- Ethics rules are not the standard of care. Defendants argue that rules of professional conduct cannot define malpractice. Desimini and Atlanta Channel followed the majority view that ethics rules are relevant evidence of the standard of care that an expert may discuss, although a violation alone does not establish liability.
- Ipse dixit standard of care. Challengers say the expert gives conclusions without sources. Atlanta Channel rejected the attack where the opinions cited the local rules of professional conduct, the Restatement and ethics opinions, but cautioned that trial testimony must stay tied to those sources.
What the public record shows
A deliberately narrow CourtListener search, "legal malpractice" AND expert AND "standard of care" AND (Daubert OR "Rule 702"), returned 24 opinions filed since 2015, as of October 3, 2026; broader searches return more. Three that show how courts handle this class of testimony:
| Outcome | Case | Court | Why |
|---|---|---|---|
| Limited | Lavina v. Satin33 Mass. L. Rptr. 434 | Mass. Super. Ct. 2016 | Applying Daubert and Lanigan, the court let the plaintiff's legal expert testify on the standard of care but struck her opinion that the underlying medical malpractice case would have settled for $1 million to $3.75 million as conjecture resting on an assumed fact and an unvetted verdict compilation. |
| Limited | Atlanta Channel, Inc. v. SolomonCiv. A. No. 15-1823 (RC) (D.D.C. Nov. 24, 2020) | D.D.C. 2020 | The court held a defense legal malpractice expert's standard of care opinions, grounded in the local rules of professional conduct and related sources, admissible under Rule 702, but struck two statements that the claims were unfounded and without merit as legal conclusions. |
| Admitted | Desimini v. Durkin2015 DNH 107 | D.N.H. 2015 | The court denied a motion to exclude or limit a legal malpractice expert, holding that her lack of divorce practice went to weight and that opinions on violations of the rules of professional conduct are relevant to the standard of care. |
Each case links to the free opinion text on CourtListener.
Under amended Rule 702
Since December 1, 2023, Rule 702 says expressly that the party offering an expert must show the court it is more likely than not that the testimony meets each requirement: that it rests on sufficient facts or data, uses reliable methods, and reflects a reliable application of those methods to the case. Questions about the basis of an opinion are no longer automatically matters of weight for the jury. For how the circuits have applied the amendment, see the Rule 702 tracker, which follows each court of appeals; for what that means for preparing or attacking this class of expert, see the guide on amended Rule 702.
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Last reviewed October 3, 2026. How this page is built: rulings are found by searching court opinions on CourtListener, and each one is read in the opinion before it is summarised here; outcomes are labelled by what the court did with the expert's testimony. No individual expert is named. This page summarises public decisions for orientation and is not legal advice; read the opinion before relying on any ruling.