Legal AI is generating measurable efficiency gains but firms cannot locate the financial return because they are looking in the wrong place
A detailed analysis published on 24 August argues that the gap between legal AI's proven operational effectiveness and its absence from law firm profit-and-loss accounts is not a measurement problem but a structural one: firms are looking for the return in billable practice work, where it is hardest to capture, rather than in non-billable operational overhead, where it is clearest. The piece, authored by Alejandro Castellano, CEO of legal AI company Caddi, argues that law firms effectively run two separate economies simultaneously. The first is the billable practice of law, tracked obsessively by utilisation and realisation rates. The second is the non-billable business of law: intake and conflicts, matter opening, docketing, time capture, billing, collections, and document management. The latter is barely measured and, precisely because it is unmeasured, is where inefficiency accumulates unchecked. The analysis identifies a structural problem with applying AI to billable work under hourly billing models: compressing a billable task compresses a billable hour, making the firm's core product cheaper to produce but harder to charge for. The honest response, the author argues, is a transition to fixed-fee or outcome-based pricing, but that is a multi-year renegotiation process, not a return in the current financial year. A further finding is that most firms lack an honest inventory of their own operational processes. Chief operating officers can list their departments and systems but cannot describe which processes run across the firm, how often, who performs them, how many tools each one crosses, or what the aggregate cost is. The result is that automation decisions are driven by whoever complained most recently rather than by evidence of where the greatest inefficiency lies.
Why this matters
The argument that legal AI's financial return is mis-located rather than absent reframes the dominant debate in law firm technology investment, shifting focus from AI adoption rates to process visibility and billing model transition. For City firms, the implication is that the firms most likely to capture AI's financial upside are those willing to move toward fixed-fee or outcome-based pricing structures, a transition with significant client relationship and partnership compensation implications. The analysis also has a direct bearing on how managing partners should evaluate AI investment proposals: ROI (return on investment) measured in billable hours saved is structurally misleading under hourly billing models.
On the Ground
This story directly affects how firms structure their legal technology and operations practices, and how they advise on technology investment and procurement. Law firms will increasingly need legal technology counsel experienced in AI tool procurement, data processing agreements with AI vendors, and governance policies for AI use in legal practice. A trainee in a legal tech or operations-adjacent role would assist with technology licence review, data processing agreement markup, AI governance policy drafting, regulatory impact assessment memos, and vendor due diligence questionnaires.
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“A managing partner asks you to evaluate whether the firm's £2m annual spend on legal AI tools is generating a return. How would you structure that analysis, and what would you expect to find?”
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