Explore how CoCounsel Legal helps law firms improve AI ROI, increase attorney productivity, and build a stronger business case for legal AI adoption.
Highlights
- Forrester’s independent study found a 400% ROI for law firms deploying Thomson Reuters CoCounsel Legal.
- CoCounsel Legal increases attorney capacity by 25% without additional headcount, transforming firm growth economics.
- Firms benefit from professional-grade AI, improved work-life balance, and measurable gains in legal work quality.
AI is no longer a future consideration for law firms – it is a present-day competitive reality. Clients are asking about it. Lateral candidates are evaluating for it. And the firms that have already made the move are quietly absorbing more work, retaining talent, and responding to clients faster than those still deliberating.
The question firm leaders are asking is not whether to invest in legal AI. It is whether that investment will pay off – and by how much, how fast, and with what degree of certainty. Thomson Reuters commissioned Forrester Consulting to directly examine the business case for Thomson Reuters CoCounsel Legal, and the results are now available.
The Total Economic Impact™ of Thomson Reuters CoCounsel Legal Cost Savings and Business Benefits Enabled By CoCounsel Legal is a rigorous, independent study that quantifies the financial return law firms can realize by deploying CoCounsel Legal.
This executive summary covers what the study found and why it matters for any firm that is serious about AI in 2026.
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What ROI has CoCounsel Legal delivered?
Capacity is the core of the story
Why the source of your AI matters
The human dimension that doesn’t show up in the headline number
Explore what CoCounsel Legal can do for your firm
What ROI has CoCounsel Legal delivered?
The bottom line: a 400% ROI, independently verified.
Forrester’s composite analysis, modeled on interviews with decision-makers at six real law firms, ranging from small practices to large global institutions, found that a representative 500-attorney firm realized:
- 400% return on investment over three years
- $18.3 million net present value
- Payback period of less than six months
These figures are risk-adjusted. Forrester applied conservative assumptions to account for slower-than-expected adoption and real-world implementation variability. The 400% return is what remained after those adjustments, making it a defensible number for internal business cases, not a best-case scenario.
For law firms and large legal departments evaluating the platform, these numbers provide a concrete framework to project return against your own firm’s data, headcount, and matter volume.
Capacity is the core of the story
The finding that resonates most with firms evaluating CoCounsel Legal is not a cost number – it is a capacity number.
Attorneys using CoCounsel Legal increased their matter capacity by 25% without adding headcount. For a firm that has historically answered growing caseloads by hiring, that changes the fundamental economics of growth.
For firms that have historically answered growing caseloads by hiring, that single figure changes the fundamental economics of growth. Before CoCounsel Legal, the firms Forrester interviewed described the same friction points again and again:
• Legal research bottlenecks: Hours spent synthesizing research that could be completed in a fraction of the time, with billable capacity lost to process.
• Document review delays: Multi-day review cycles that created downstream scheduling pressure across entire matters.
• Heavy onboarding costs: The unbillable time required to get up to speed on new or inherited matters, compounding with every new client.
CoCounsel Legal’s integration into research, drafting, and document workflows addresses each of these friction points directly, and the capacity that gets unlocked flows into revenue.
The full breakdown of how that capacity translated to dollars, including adoption rate assumptions, year-by-year projections, and Forrester’s risk adjustments, is available exclusively in the complete study.
Because CoCounsel Legal is backed by Westlaw, I have a level of confidence and certainty in what it’s doing.
-Founding partner, Criminal defense
Why the source of your AI matters
Not all AI tools are appropriate for legal work. Attorney obligations to clients, courts, and licensing bodies mean that accuracy, sourcing, and governance are baseline requirements – not optional features.
As content quality and AI reliability have become front-line concerns for the profession, the firms in Forrester study took a deliberate approach. Several adopted formal governance policies that designated CoCounsel Legal as the only approved generative AI tool firmwide. That decision was grounded in the platform’s foundation on Westlaw, Thomson Reuters’ authoritative legal research database.
For firms navigating competing AI claims in a crowded market, that foundation is not incidental. It is why CoCounsel Legal holds up under professional scrutiny and why governed, purposeful AI adoption is itself a competitive differentiator.
The human dimension that doesn’t show up in the headline number
The financial model tells one story. The attorney interviews behind it tell another.
Attorneys described a meaningful shift in how they spend their time away from repetitive, manual work that dominates a typical day and toward the judgment, argument development, and client interaction that define the real value of legal expertise.
CoCounsel Legal allows me to spend more time crafting my arguments because I’m spending less time searching for things.
-Managing partner, Insurance defense
- Work-product quality: Measurable improvement in the quality of attorney outputs and deliverables to clients.
- Fewer write-downs: Reduction in time written off as non-billable, improving realization rates firmwide.
- Attorney work-life balance: Attorneys reported meaningful gains in balance and reduced after-hours workload.
- Junior attorney satisfaction: Measurable increase in job satisfaction among associate and junior attorney ranks.
Behind every one of those measurable gains is the human intelligence at the core of CoCounsel Legal – the attorney-editors, legal specialists, engineering leaders, and AI reliability experts who ensure every capability is grounded in professional-grade standards.
And what Deep Research has made possible in legal work illustrates how that human foundation translates into genuine changes in how legal work gets done, not just how fast it gets done.
Explore what CoCounsel Legal can do for your firm
The numbers summarized here are the starting point, not the complete argument. The Total Economic Impact™ of Thomson Reuters CoCounsel Legal Cost Savings and Business Benefits Enabled By CoCounsel Legal contains the complete financial model, including year-by-year benefit and cost projections, the detailed assumptions behind each figure, sensitivity analysis, and the qualitative findings that explain what actually drives the return in practice.
The data is in – download the complete Forrester Total Economic Impact™ study and see exactly what CoCounsel Legal could mean for your firm’s growth. ↓
Case study
A Forrester Consulting study of real law firms using generative AI in legal practice today.
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