Westlaw vs. Lexis vs. Bloomberg Law

Platform Overview

The legal research market is dominated by three major platforms: Westlaw (owned by Thomson Reuters), Lexis+ (owned by RELX), and Bloomberg Law (owned by Bloomberg LP). While all three provide access to case law, statutes, regulations, and secondary sources, each has distinct strengths that make it better suited for particular research tasks.

As a law student, you likely have access to all three through your school. Learning when to use each platform will make you more efficient and thorough in your research. After graduation, your employer will typically subscribe to one primary platform, so understanding the differences helps you adapt and advocate for additional resources when needed.

Westlaw Edge

Westlaw, part of Thomson Reuters, traces its roots to the West Publishing Company, which began classifying cases in the 1870s. This heritage gives Westlaw its greatest competitive advantage: the Key Number System.

Core Strengths

The Key Number System

West's Key Number System is the most comprehensive subject classification of American case law. West editors read every published case and classify each legal point into one of approximately 450 topics and tens of thousands of Key Numbers. This allows you to:

• Find all cases addressing a specific legal point across jurisdictions
• Navigate from one relevant case to all others on the same issue
• Browse legal topics hierarchically to discover related concepts
• Track how courts have treated an issue over decades using consistent classification

No other platform offers anything comparable. If you're doing deep case law research, Westlaw's Key Numbers are unmatched.

Consistent, High-Quality Headnotes

Westlaw's editorial headnotes are written by attorney-editors and use consistent terminology across cases. This consistency—maintained for over a century—means that searching within headnotes often produces more precise results than full-text searching.

Practical Law

Practical Law provides practice-ready resources including checklists, templates, standard documents, and how-to guides written by practicing attorneys. It covers transactional work, litigation, and regulatory compliance with resources that can be adapted for client matters. This is particularly valuable for junior associates who need to learn practice workflows quickly.

KeyCite

Westlaw's citator provides clear visual indicators of case status (red flag for negative treatment, yellow flag for caution, etc.) and includes "depth of treatment" bars showing how extensively a citing case discusses your case. The KeyCite graphical view shows citation relationships visually.

Key Features

• KeyCite Overruled — Identifies cases that have been implicitly overruled, even if never expressly so
• Statutes Compare — Side-by-side comparison of statutory language across different versions
• Litigation Analytics — Data on judge behavior, motion outcomes, case timelines, and attorney success rates
• WestSearch Plus — AI-powered search that combines natural language with Key Number classification
• Westlaw Precision — Natural language research assistant (integrated AI tool)
• Folders — Organize and annotate research with collaboration features

Best Use Cases

• Case law research — Especially when you need to find all cases on a legal point using Key Numbers
• Verifying cases — KeyCite provides clear, reliable citation information
• Historical research — Consistent classification makes tracing legal developments easier
• Transactional templates — Practical Law provides excellent starting points
• Litigation planning — Analytics on judges and opposing counsel

Lexis+

Lexis (now branded Lexis+) has been Westlaw's primary competitor for decades. While it lacks the Key Number System, it compensates with strong search functionality, excellent news and public records coverage, and increasingly sophisticated AI tools.

Core Strengths

Search Within Results

Lexis's "Search Within Results" functionality is more flexible than Westlaw's equivalent. You can iteratively narrow your search results by adding terms, making it easier to refine a large result set without starting over. This is particularly valuable when your initial search returns hundreds or thousands of results.

Shepard's Citations

Shepard's, the original legal citator, provides detailed treatment analysis for cited cases. Many researchers find Shepard's treatment categories (followed, distinguished, criticized, etc.) more granular than KeyCite's. Shepard's also provides "Shepard's at Risk" alerts that identify cases with potential validity issues.

News and Public Records

Lexis has significantly broader coverage of news sources, including many international publications, business news, and industry-specific sources. Its public records database (available in some subscriptions) includes court filings, verdicts, settlements, and jury information that can be valuable for litigation research.

Practice Area Pages

Lexis organizes content by practice area with curated starting pages that provide relevant forms, treatises, cases, and current awareness for specific legal specialties.

Key Features

• Lexis+ AI — Conversational AI research assistant with document drafting capabilities
• Headnote and Topic System — Lexis has its own classification system, though less comprehensive than Key Numbers
• Ravel View — Visual mapping of how cases cite each other
• Context — Provides data on judge analytics, expert witnesses, and litigation trends
• Brief Analysis — Extracts key authorities from uploaded briefs
• Practical Guidance — Practice guides, forms, and templates (competitor to Practical Law)

Best Use Cases

• News research — Superior coverage of news, business, and public records
• Iterative searching — Search Within Results is excellent for refining large result sets
• Expert witness research — Comprehensive expert witness depositions and testimony
• International research — Broader coverage of international sources and comparative law
• Shepard's verification — Some researchers prefer the granular treatment analysis

Bloomberg Law

Bloomberg Law entered the legal research market in 2009, much later than Westlaw and Lexis. It leverages Bloomberg's core competency in financial data and news to offer unique value for corporate, transactional, and regulatory work.

Core Strengths

Transactional Content

Bloomberg Law excels at transactional research. It provides access to SEC filings, M&A deal documentation, corporate governance materials, and sample transaction documents searchable by deal type, industry, and terms. For attorneys working on mergers, securities offerings, or financing transactions, Bloomberg's deal databases are unmatched.

Docket and Litigation Analytics

Bloomberg's docket database includes federal court filings with sophisticated search and analytics. You can track litigation against specific companies, analyze filing patterns, search for specific motion types across cases, and access exhibits and pleadings from ongoing litigation.

Integration with Bloomberg Terminal

For users with access to the Bloomberg Terminal (common in finance-related practice), Bloomberg Law integrates financial data, company information, and market analysis directly into legal research workflows.

Regulatory and Legislative Tracking

Bloomberg provides excellent tracking of pending legislation and regulations, with analysis of how proposed changes might affect specific industries or practice areas. The Daily Labor Report, Daily Tax Report, and similar Bloomberg Intelligence products provide expert analysis of regulatory developments.

Key Features

• BCite — Bloomberg's citator with "Direct History" and "Citing Documents" analysis
• Points of Law — Bloomberg's case classification system (similar to Key Numbers but less mature)
• Draft Analyzer — AI tool that reviews briefs and contracts for issues
• Bloomberg Intelligence — Industry and company analysis from Bloomberg analysts
• Transactional Intelligence Center — Database of M&A deals, financing transactions, and terms
• BBNA Practice Centers — Expert analysis in tax, labor, health, environment, and other areas
• Practical Guidance — Practice guides and forms from Bloomberg BNA experts

Best Use Cases

• M&A and securities work — Deal databases, SEC filings, and transaction documents
• Corporate research — Company information, ownership data, and financial filings
• Docket research — Finding complaints, motions, and exhibits from federal litigation
• Regulatory compliance — Tracking proposed rules and expert analysis
• Business intelligence — Industry analysis integrated with legal research
• Tax and labor law — Bloomberg BNA has long been authoritative in these areas

Feature Comparison Table

The following table compares key features across all three platforms. Keep in mind that all platforms continuously add features, so check current offerings when making decisions.

Case Law Features

Statutory Features

Citators

Secondary Sources

AI Tools

Search Capabilities

Specialized Content

When to Use Each Platform

Knowing which platform to choose for specific tasks will make your research more efficient. Here are practical recommendations based on research type.

Choose Westlaw When:

• You need comprehensive case classification — The Key Number System is unmatched for finding all cases on a specific legal point
• You have one good case and want to find related cases — Click the Key Number from a relevant headnote to find similar cases
• You're doing historical legal research — Consistent classification since the 1870s aids tracking legal developments
• You need transactional templates — Practical Law provides excellent starting documents with explanatory notes
• You want to analyze litigation data — Litigation Analytics provides judge behavior and attorney performance data
• You're concerned about implicit overruling — KeyCite Overruled identifies cases overruled by implication

Choose Lexis+ When:

• You need to iteratively refine searches — Search Within Results is more flexible than other platforms
• You're researching news and media coverage — Lexis has the broadest news database
• You need public records or background information — More comprehensive public records access
• You want detailed citation treatment analysis — Shepard's treatment categories are more granular
• You're researching expert witnesses — Better coverage of expert depositions and testimony
• You're doing international or comparative research — Broader coverage of international sources

Choose Bloomberg Law When:

• You're working on M&A or corporate transactions — Deal databases and transaction documents are excellent
• You need SEC filings with analysis — Superior coverage with business context
• You want to search federal court dockets — Comprehensive docket search with access to filings
• You're tracking regulatory developments — Expert BNA analysis of pending rules
• You need business intelligence — Bloomberg Intelligence integrates company and industry analysis
• You're researching tax or labor law — Bloomberg BNA has long been authoritative in these areas

Search Syntax Comparison

All three platforms support Boolean (Terms & Connectors) searching, but the syntax varies slightly. Here's a reference guide for common operators.

Basic Boolean Operators

Proximity Operators

Wildcards and Truncation

Search Syntax Examples

Cost Considerations for After Graduation

During law school, you have free or heavily subsidized access to all major platforms. After graduation, the economics change dramatically. Understanding pricing structures helps you plan your career and advocate for resources.

General Pricing Overview

Legal research platforms use several pricing models:

• Flat-rate subscriptions — Unlimited access for a monthly or annual fee; typical for larger firms
• Transactional pricing — Per-search or per-document charges; common for smaller firms and solo practitioners
• Hybrid models — Base subscription plus charges for premium content or heavy usage

Actual prices vary enormously based on firm size, negotiation, and specific content packages. A large firm might pay hundreds of thousands of dollars annually for full access, while a solo practitioner might pay a few hundred dollars monthly for limited access.

Large Firm Practice

Large law firms typically subscribe to at least one major platform (usually Westlaw or Lexis) and often have access to multiple platforms. As an associate, you'll generally have unlimited access to whatever the firm subscribes to. Key considerations:

• Learn what platforms your firm subscribes to during interviews or orientation
• Understand any usage tracking or cost allocation policies
• Know how to request access to additional platforms when needed
• Efficiency matters—unnecessary searches may be tracked

Small Firm and Solo Practice

Smaller practices often cannot afford comprehensive subscriptions to major platforms. Strategies include:

• Choose one platform — Select based on your practice area (Westlaw for litigation/Key Numbers, Bloomberg for transactional, etc.)
• Use limited subscriptions — Many platforms offer practice-area-specific or jurisdiction-specific packages at lower costs
• Supplement with free resources — Google Scholar, state court websites, and government sources (see Free Resources)
• Consider alternatives — Services like Fastcase (often free through bar associations), Casetext, and vLex offer lower-cost options
• Use library access — Many bar associations and courthouse libraries provide free or low-cost access

Public Interest and Government

Public interest organizations, government agencies, and legal aid often have limited budgets for research tools:

• Negotiate nonprofit rates — All major platforms offer discounted rates for qualifying organizations
• Leverage free resources — Government sources, Google Scholar, and state court websites
• Use law school access — Many law schools allow alumni limited access or provide research assistance
• Bar association benefits — Many state bars include Fastcase or Casetext in membership

In-House Practice

Corporate legal departments have varying approaches to research tools:

• Many large companies subscribe to one or more major platforms
• Bloomberg Law is particularly common in financial services given Terminal integration
• Some departments rely primarily on outside counsel for intensive research
• Industry-specific databases may be available through the business side

Platform Comparison for Budget-Conscious Practitioners

If you can only afford one platform, consider these factors:

Summary: Quick Reference Guide

Use this summary to quickly decide which platform to use for common research tasks:

Next Steps

Now that you understand the differences between platforms, continue developing your research skills:

• AI Legal Research — Learn how AI tools on each platform work and their limitations
• Free & Low-Cost Resources — Alternatives when premium platforms aren't available
• Citators — Deep dive into KeyCite and Shepard's for verification
• Case Law Research — Master the techniques that work across all platforms