“Half my advertising is wasted. I just don’t know which half.” That old marketing adage still applies to legal, but knowing your law firm advertising budget benchmarks and modern measurement makes the unknown portion smaller. Here’s how to measure what matters.
The Attribution Challenge
Legal advertising attribution is complex because:
Multi-touch journeys are common. Someone sees your TV ad, later searches your name, clicks a Google result, then calls. Which channel gets credit?
Time lag is significant. Weeks or months can pass between first impression and retained case.
TV/CTV drives downstream effects. Brand advertising creates branded search and direct traffic, which often get credited to Google Ads or “direct” in last-click models.
Offline conversion matters. Google Analytics doesn’t see phone calls, intake consultations, or signed retainers.
These challenges don’t make measurement impossible. They make it more sophisticated.
The Metrics That Matter
Lead-Level Metrics
Cost Per Lead (CPL). What you pay for each inbound inquiry.
Benchmarks from a 49-firm dataset:
| Case Type | Average CPL |
|---|---|
| Slip and fall | $312 |
| Workplace injury | $354 |
| Auto accidents | $391 |
| Product liability | $476 |
| Medical malpractice | $512 |
These are blended averages across all channels. Your specific CPL depends heavily on market, channel mix, and campaign quality.
Lead Quality Score. Not all leads are equal. Track what percentage of leads are:
- Qualified (right case type, liability, damages)
- Contactable (valid phone/email, answers)
- Within geography
- Not already represented
Case-Level Metrics
Lead-to-Case Conversion Rate. What percentage of leads become signed cases?
Industry range: 15-30%, depending on case type and intake quality.
Cost Per Signed Case. The metric that actually matters.
If your CPL is $400 and you close 20%, your cost per signed case is $2,000. If you close 30%, it’s $1,333.
Many PI Google Ads campaigns see $600-$1,000+ CPL and $1,500-$5,000+ cost per signed case. This math works when case values are in six figures.
Channel-Specific Metrics
For Google Ads/LSAs:
- Click-through rate (CTR)
- Conversion rate
- Quality Score
- Cost per conversion
For TV/CTV:
- Branded search lift during flights
- Direct traffic changes
- Call volume correlation
- Brand awareness surveys
For All Channels:
- Attribution window conversions
- Assisted conversions
- View-through conversions (for display/video)
Measuring TV and CTV
“TV can’t be measured” is a myth. It’s more complex than digital, but measurable:
Direct Response Tracking
Vanity URLs: Unique URLs mentioned in spots (e.g., SmithLaw.com/TV)
Unique Phone Numbers: Dedicated tracking numbers for TV campaigns
Call Tracking: Timestamp calls against ad airings to correlate
Indirect Response Tracking
Branded Search Lift: Did searches for your firm name increase during the TV flight?
Direct Traffic Lift: Did website direct visits increase?
Overall Lead Volume: Did total leads increase proportionally to spend?
Brand Lift Studies
Survey-based measurement of:
- Awareness (unaided and aided)
- Consideration
- Message recall
- Brand associations
Modeled Attribution
Statistical models that estimate TV’s contribution by analyzing:
- Lead volume patterns
- Timing correlations with airings
- Market-level variations
- Holdout market comparisons
Building a Measurement Framework
Measurement Framework Setup
Connect the Data
Integrate ad platforms (Google, Meta, CTV DSPs), call tracking (CallRail, etc.), CRM/Case management, and website analytics. Goal: See the journey from impression → click → call → lead → signed case.
Define Your Conversion Actions
What counts as success? Phone call over 60 seconds? Form submission? Intake appointment scheduled? Retainer signed? Be consistent across channels for fair comparison.
Establish Benchmarks
Know what “good” looks like: CPL by case type, lead-to-case conversion rate, cost per signed case, and acceptable CAC relative to case value.
Choose Attribution Modeling
Options: Last-click (simple but misleading), First-click (credits awareness), Linear (equal credit), Time-decay (more to recent), or Data-driven (algorithm-based). For PI, blended models work best.
Report on What Matters
Executive reporting: cost per signed case by channel, total case volume, ROAS, trend lines. Operational reporting adds CPL by campaign, conversion rates, lead quality distribution.
The Measurement Gap Most Firms Miss
Most firms measure the bottom of the funnel well (leads, calls, cases) but poorly measure the top (awareness, brand lift, consideration).
This creates a systematic bias toward channels that look good in last-click attribution (Google, LSAs) while undervaluing channels that create demand (TV, CTV, social).
Travelers and ATRA link legal advertising to real financial outcomes: increased claims and settlements. The advertising works. The question is whether your measurement captures the full picture or just the final click.