Do small law firms misuse AI more often than large ones?
A database of 114 court cases with AI-tainted filings shows 90 percent involved small or solo firms. But does this reflect higher misuse rates, or simply better detection of errors in smaller practices?
Riana Pfefferkorn counts 114 US court cases from Damien Charlotin's AI Hallucination Cases database, each one a filing that opposing counsel or the court found to contain inaccuracies "suspected or shown to have been caused by the use of AI." In that sample, 90 percent of the firms involved are solo practices or small firms (solos 50.4 percent, firms of 2 to 25 lawyers 39.5 percent), and the hallucinations are attributed to plaintiff's counsel in 56.1 percent of cases against 30.7 percent for defendants. Of the 34 cases that name a tool, ChatGPT appears in 18. Pfefferkorn presents this as confirming what "many lawyers and judges may have suspected": the archetype is "a small or solo law practice using ChatGPT in a plaintiff's-side representation."
Her explanation is about capacity more than the tool. Lawyers "struggle with busy caseloads, the trustworthiness of their co-counsel, junior attorneys, and support staff," and personal demands compete with work, and "that was already true long before AI." AI "merely provided a new way to make those errors" while "promising a way out of the underlying issues" such as time crunches and thin support. The second half of her argument comes from a Stanford study she cites, which found "disturbingly high levels of hallucinations in all the tools they studied." She places the costs on clients, opposing counsel and courts, not only on the lawyers who are sanctioned.
The vendor side of this is the study in How often do legal AI tools actually hallucinate citations?. Pfefferkorn notes that the companies behind the four products it tested (GPT-4, Lexis+ AI, Westlaw's AI-Assisted Research and Ask Practical Law AI) all appear among the 34 named-tool cases. That connects a measured failure rate to a courtroom record, though the excerpt does not say which product was used in which filing. The admissions study is a useful contrast: Does AI essay use hurt admissions chances despite quality gains? compares flagged users with comparable non-users, whereas this count has no comparison group at all. The problem of what a detection channel can see also recurs in Why did AI article share stop growing after 2025?: a database holds only the incidents someone found.
What the excerpt does not establish is a denominator. The 114 cases are incidents found in one database, covering US courts from June 2023 to October 7, 2025, with pro se matters excluded. There is no count of how many filings each firm type produces, so "90 percent" is a share of caught cases, not a rate of AI misuse by firm size. If large firms have their errors caught or reported less often, the sample understates them, and the excerpt cannot tell. Solo status and firm size were partly guessed from third-party reporting that Pfefferkorn flags as possibly outdated, and the tool breakdown covers only 34 of 114 cases (30 percent). The defensible reading is that detected AI-tainted filings cluster in small, plaintiff-side practice. Claims that small firms use AI more, or err more per filing, would need a base of AI-assisted filings by firm size that this sample does not provide.
Inquiring lines that read this note 10
This note is a source for these research framings, grouped by the broader line of inquiry each explores. Scan the bold lines of inquiry; follow any specific question forward.
What are the real-world consequences of AI citation hallucinations?- Does speed improvement from AI assistants carry over to billable legal work?
- Why might opposing counsel catch small firm errors more often?
- How many AI-assisted filings does each firm size actually produce?
- What percentage of AI hallucination cases result in actual court sanctions?
- Do solo practitioners face different sanction outcomes than large law firms?
- Do solo lawyers face different citation hallucination risks than large firms?
- Why do lawyers need provenance tracking more than other professions?
- How much do existing legal AI tools actually hallucinate in practice?
Related concepts in this collection 3
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How often do legal AI tools actually hallucinate citations?
Legal vendors claim their AI research tools eliminate hallucinations, but do they? This preregistered study measures hallucination rates in leading commercial legal-research systems to test those marketing claims.
the study the excerpt cites; its tool failure rates sit beside a courtroom record of who filed the errors
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Does AI essay use hurt admissions chances despite quality gains?
This study explores whether applicants who use AI to write essays face admission penalties, even when those essays show higher writing quality. The tension matters because it suggests institutions may discount AI-assisted work regardless of its objective merit.
contrast: the admissions study compares flagged users with non-users; this count has no comparison group
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Why did AI article share stop growing after 2025?
Graphite reports a plateau in AI-generated articles at 50% but cannot distinguish whether search engines penalize AI content, detection tools are missing more AI text, or both. The excerpt leaves this critical cause untested.
parallel: both counts see only what a detection channel finds, so their coverage is unknown
Related papers in this collection 8
Papers most semantically related to this note, ranked by cosine similarity in the embedding space.
- Who's Submitting AI-Tainted Filings in Court?
- Lawyering in the Age of Artificial Intelligence
- Hallucination-Free? Assessing the Reliability of Leading AI Legal Research Tools
- The UN's AI Panel Sees Misalignment. We See Corporate (Mis)Behavior.
- Ordinary, Reasonable Chatbots: Do AI Models Track Human Legal Judgments?
- PACT: Can Enterprise AI Assistants Be Trusted Under Pressure?
- Scientific production in the era of Large Language Models
- Reimagining Legal Fact Verification with GenAI: Toward Effective Human-AI Collaboration
Original note title
Pfefferkorn finds solo and small firms account for 90 percent of 114 US court cases with AI-tainted filings — and plaintiffs' counsel 56 percent