The Model Rules of Professional Conduct are clear about what must happen when a lawyer makes a “material mistake”, and the steps are grounded in the duty of competence, diligence, and communication owed to a current client.
The Ethical Framework
ABA Model Rule 1.1 requires legal knowledge and thoroughness. Rule 1.3 requires promptness, and Rule 1.4 mandates keeping clients informed about their matter and promptly responding to requests for information.
When a mistake has been made during a legal representation, these rules all come into play. If the error is “material,” it must be disclosed promptly. Hoping the client never finds out or quietly fixing it before disclosing is never a good idea as it can risk turning a simple lapse into a Rule 8.4(c) problem involving deceit or misrepresentation.
What Counts as a“Material Mistake”?
The ABA addressed this question in Formal Opinion 481, which describes a “material mistake” as (1) an error reasonably likely to harm or prejudice the client’s interests, or (2) that a reasonable client would want to know about to make informed decisions.
Examples include missing a filing deadline, failing to raise a claim, giving incorrect legal advice, or any oversight that limits the client’s legal position. Modern practice errors such as signing a filing with hallucinated cases, citations, or quotations probably fall into this “material” category. By contrast, small mistakes—an actual typo, a short delay, or a minor procedural misstep—may not be material enough to require disclosure if they can be quickly corrected.
Tell the Client
When a material mistake has been made, client disclosure should be prompt, factual, and transparent. Rule 1.4 Comment 7 makes it clear that withholding information from the client because it may cause you harm is forbidden. The client should be told what happened, what it means for their rights, what can be done to fix it, and what choices they have, including whether they should seek independent advice.
The duty to disclose exists only during the representation. Once the representation ends, there is no ongoing duty to contact former clients to confess past mistakes unless silence would perpetuate a fraud or violate another rule.
Fix the Mistake and Watch for Conflicts
Once the error has been disclosed, diligence requires quick action to repair the damage. That might mean filing a motion for relief, disclosing information to the court under the duty of candor (Rule 3.3), or negotiating with the opposing party to limit prejudice to the client’s case. Because lawyers are fiduciaries to their clients, work done to undo a mistake—whether material or not—is not billable.
Also be aware that if your personal interest in avoiding liability could limit the ability to give independent advice about the mistake, that conflict may require withdrawal under Rules 1.7(b) and 1.16(a)(1).
Lead with Ethics, not Fear
Every lawyer makes mistakes, so don’t practice afraid. Practice prepared. Know your duties, act quickly if you do make a mistake, and remember that owning a mistake the right way is one of the strongest demonstrations of professionalism.
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