For lawyers, the buzz around AI can come with a healthy dose of hesitation. You may have heard stories about attorneys making headlines for relying on AI-generated case law, warnings about AI hallucinations, or simply wondered: How can I trust this tool?
Those concerns are understandable and they're worth taking seriously. AI can draft an email, summarize a deposition, organize case information, brainstorm arguments, help you get up to speed on a matter in seconds, and more. But it can also produce information that is incorrect or misleading. That instance is known as an AI hallucination.
If you’re using—or even just exploring—generative AI, understanding hallucinations is an important part of learning to use the technology responsibly. AI has enormous potential to help lawyers work more efficiently, and hallucinations aren’t a reason to shy away from the technology. By understanding what hallucinations are, what to look for, and where verification and human judgment come into play, lawyers can use AI responsibly and with greater confidence.
Let’s break down what AI hallucinations are, why they happen, and the practical steps lawyers can take to manage them.
What is an AI hallucination?
An AI hallucination happens when an AI tool generates information that sounds convincing but is inaccurate or misleading. Hallucinations aren’t always easy to spot, because they don’t always look like mistakes.
An hallucination may be polished, detailed, authoritative, and formatted exactly as you would expect. A fabricated case citation can look like a real citation, an inaccurate summary can sound perfectly reasonable, and an incorrect piece of information can appear alongside several correct ones.
Want a broader introduction to the technology behind all of this? Download The Beginner’s Guide to AI for Law Firms for a plain-English walkthrough of AI, generative AI, prompts, hallucinations, responsible use, and practical ways law firms can begin using AI.
Why do AI hallucinations happen?
Generative AI is designed to generate a response.
It learns patterns from large amounts of information. When you give it a prompt, it uses those patterns—along with the context you provide—to predict what a useful response should look like.
You ask → AI predicts → AI responds
That ability to predict and generate is what makes AI so useful. However, prediction isn’t the same as knowing.
If an AI tool doesn’t have enough information to accurately answer a question, it may still generate a response based on the patterns it recognizes. And because it’s very good at generating natural, convincing language, that response can sound completely accurate even when a detail isn’t.
That’s how a hallucination happens.
AI is an incredibly capable assistant: it can help you get to a strong starting point faster, while your legal knowledge and professional judgment determine what crosses the finish line.
Examples of AI hallucination in legal work
The most infamous examples involve fake case citations.
For example, attorneys submitting a filing containing fictitious cases generated by ChatGPT. Instead of independently confirming the authorities through established legal research sources (think Thomson Reuters and Westlaw), they ask ChatGPT whether the cases are real and roll with it. The result is likely sanctions.
But fake cases aren't the only form an AI hallucination can take. Depending on the tool, task, and information available to it, hallucinations could look like:
- invented or misstated cases, statutes, quotes, dates, or factual details
- incorrect document summaries
- sources wrongly attributed to information
- outdated or incomplete explanations
The problem isn't using AI. It's relying on AI without verification.
How lawyers can reduce the risk of AI hallucinations
The headline from the cautionary stories should be “lawyers remain responsible for their work.”
Like an extremely eager summer associate, AI is fast, produces impressive first drafts, and helps you work through large amounts of information. But you wouldn't take a brief from a summer associate, skip your review, and immediately file it with the court.
AI use requires the same supervision and there are habits and workflows that make it much easier to catch hallucinations.
1. Independently verify legal authorities
If an AI tool gives you a case, statute, quotation, rule, or other legal authority, don't rely on the AI-generated response as your verification.
Confirm the authority through an appropriate primary source or trusted legal research platform.
2. Ask for sources but still check them
Asking an AI tool where information came from can make reviewing an answer easier.
Useful follow-up prompts might include:
- “What sources support this response?”
- “Can you provide the source for this statement?”
- “What information are you relying on for this answer?”
- “Can you point me to the primary source?”
A source supplied by AI isn't automatically trustworthy, either. Treat it as a starting point for verification, click on the link and double-check.
3. Give stronger context during input
Clear prompts help AI understand the task you want it to perform.
Instead of:
“Summarize this.” Try “Summarize this deposition transcript. Identify the key testimony, any apparent inconsistencies, and areas that may require follow-up. Base your response only on the attached transcript, and identify where in the transcript each point appears.”
Detailed instructions don't magically eliminate hallucinations, but they can constrain the task and make the output easier for you to review.
4. Start using AI with low-risk tasks
Not every task carries the same weight.
If you're getting started with AI in the workplace, consider experimenting with lower-risk work such as creating checklists, brainstorming ideas, organizing non-sensitive notes, or drafting internal communications.
As you become more comfortable with the functions—and understand a particular tool's privacy, security, and verification features—you can make more informed decisions about where AI fits into your workflow.
5. Choose tools that are tailor made for legal work
Our favorite tip for mitigating hallucinations is to invest in legal specific AI tools. Consumer AI tools (like Claude and ChatGPT) are designed to answer a wide range of questions, but won’t have access to all the sources or context needed for comprehensive legal work.
Legal AI tools are built specifically for legal professionals and offer access to legal sources, matter-specific context, and features that make outputs easier to verify. These tools often offer privacy, security, workflow, and verification capabilities specifically built around legal work.
Hallucinations shouldn't stop you from utilizing AI
AI hallucinations are something lawyers should get familiar with, but not something that should keep you from exploring what AI can do for your practice.
With the right tools, thoughtful verification, and your legal judgment firmly in the driver’s seat, AI can help take time-consuming work off your plate while you stay in control of the final product.
Looking to get more comfortable with AI? The Beginner’s Guide to AI for Law Firms breaks down the fundamentals, practical use cases, and responsible AI practices in plain English.
