Allen & Overy's 3,500 lawyers put Harvey AI to work, asking 40,000 questions in trial

As a global law firm with more than 3,500 lawyers, Allen & Overy (A&O) faced the perennial challenge of manual legal research and drafting consuming significant attorney time across day-to-day client work. Even small per-lawyer inefficiencies compound into major costs at the firm's scale.

A&O became the first law firm to adopt Harvey, a ChatGPT-style AI assistant built by a US team including former lawyers, using natural language processing, machine learning, and data analytics. The firm ran a trial since November 2022, rolling access out to its lawyer base as an initial research and drafting tool intended to augment rather than replace legal work, with outputs requiring careful accuracy review.

During the trial, roughly 3,500 lawyers asked Harvey about 40,000 questions for client work, which A&O described as showing "amazing results." The firm expects the tool to save individual lawyers a few hours of work per week, a saving projected to become more significant firm-wide as the tool improves over time.

• Being first-to-market with a generative AI legal assistant at enterprise scale generated substantial internal adoption (40,000 queries from 3,500 lawyers) in just a few months.
• Even modest per-lawyer time savings compound into meaningful cost impact at large-firm scale.
• Vendors and adopters both frame the tool as an augmentation layer, not a lawyer replacement, with human review of outputs still required.