How to Track Cost Per Case from Radio Advertising for Personal Injury Firms

Your radio station sends a monthly report: reach, gross rating points, estimated impressions. None of it tells you how many cases you signed. Radio is one of the largest line items in many PI advertising budgets—AM drive-time, sports radio, talk radio, Spanish-language formats—and it is one of the hardest channels to attribute accurately. Most PI firms are flying blind on it.

Without a deliberate attribution setup, radio becomes a faith-based budget line. You keep running it because calls feel like they come in when you're on the air. You cut it under budget pressure because you can't defend it with data. Neither decision is made with real cost-per-case information.

This guide covers a three-method attribution framework that connects radio spend to signed cases—so you can calculate a real cost per case, benchmark radio against your other channels, and make budget decisions based on outcomes, not intuition.

Why Radio Is Harder to Attribute Than Digital Channels

Digital channels have a built-in attribution advantage. A user who clicks a Google ad generates a session ID, a click timestamp, and a conversion event your CRM can capture. Radio generates none of that. A listener hears your spot during morning drive, thinks about it, and calls four days later when they finally decide to get legal help. The connection between impression and call is invisible unless you build a system to surface it.

There's also a longer intent-to-action cycle at play. A prospect who searches “personal injury attorney near me” is in active buying mode. A prospect who hears your radio spot is in awareness mode—they may not need legal help yet. When they do, they reach for the number they remember. That delay is exactly why a 30-day attribution window consistently undercounts radio performance.

Despite these challenges, radio attribution is achievable. The same frameworks that work for TV and billboard apply here: dedicated tracking numbers, structured intake questioning, and geo-lift analysis. Used together, they recover the majority of radio-attributed cases and produce a cost-per-case number you can put on the same dashboard as Google, Facebook, and aggregator spend.

Method 1: Dedicated Tracking Numbers by Station and Daypart

The most direct method: a phone number that exists exclusively in your radio advertising. When that number rings, the call is radio-attributed by definition.

Assign a unique CallRail number to each station you advertise on. If you run spots across multiple dayparts on the same station—morning drive and evening drive, for example—use separate numbers for each daypart. This lets you compare not just station performance, but time-of-day performance. Morning drive on a sports station may produce a very different cost per case than that same station's weekend programming.

Three rules that matter:

• Never reuse a tracking number across channels.A number that appears on both a radio spot and a direct mail piece cannot tell you which channel generated the call.
• Run the tracking number for the life of the attribution window.If you pull the number three weeks after a flight ends, you will miss calls from prospects who heard your spot but acted later. Keep radio tracking numbers live for at least 90 days after a flight.
• Include the tracking number in every creative.Spots that only mention a vanity URL (“call us at AccidentHelpNow.com”) redirect to digital and lose the radio attribution signal.

Method 2: Structured Intake Questioning

Tracking numbers capture direct-dial calls. They miss the prospect who heard your spot, searched your firm name on Google, and called the website number. Structured intake questioning closes that gap.

Every intake call needs a source question with a forced-choice dropdown—not a free-text field. Free text generates dozens of radio variants (“heard it on the radio,” “radio ad,” “AM station”) that can't be aggregated. A dropdown produces one clean tag per call.

Build your radio options with format specificity:

• Radio / AM Talk
• Radio / Sports (and name the station if you're on multiple)
• Radio / Spanish Language
• Radio / Other

When a caller says they heard you on the radio, intake tags the format. That tag flows to the case record in your CRM and, eventually, to your cost-per-case calculation. This method typically recovers an additional 20–30% of radio-attributed cases beyond what tracking numbers capture alone.

Method 3: Geo-Lift Analysis for Brand-Level Attribution

Some radio exposure converts through brand search, not direct call. A prospect hears your name on the radio, searches it on Google, and clicks your website listing. In standard attribution, that call is logged as branded search—not radio.

Geo-lift analysis compares branded search volume and inbound lead volume during radio flight weeks against non-flight weeks in the same market. A consistent 12–18% lift in brand search during active flight weeks indicates radio influence. It is not precise attribution, but it gives you a defensible estimate for the brand-building portion of your radio spend that tracking numbers and intake tags cannot reach.

You need at least three to four flight periods to establish a reliable pattern. Use geo-lift as a supplemental signal, not a primary source. Tracking numbers and intake tags are your core data. Geo-lift is the adjustment that keeps you from systematically undervaluing radio.

What Cost Per Case from Radio Actually Looks Like

PI firms with full radio attribution see wide variation by format. Drive-time AM and PM slots on talk and news stations carry premium spot rates and typically produce cost per case of $3,500–$6,500. Sports radio—particularly local NFL and NBA affiliates during season—runs $2,500–$5,000 per case in markets where the audience skews toward auto accident demographics. Weekend and off-peak programming costs less per spot but often produces a higher cost per case because audience concentration is lower.

Spanish-language radio is worth tracking as its own line. In markets with large Hispanic populations, Spanish-language formats often produce cost per case well below a firm's blended average—lower competitive pressure and higher conversion rates from bilingual intake teams. Firms that don't segment Spanish-language radio bury a genuine performance advantage in their overall number.

Why the 90-Day Attribution Window Is Non-Negotiable for Radio

The most common radio attribution mistake is measuring on a 30-day window. Radio does not work like paid search. A prospect who hears your spot during morning drive on a Monday may not be in an accident until the following month. When they call, they remember “that attorney I hear on the radio”—not a specific ad date.

PI firms with mature radio attribution programs consistently find that 35–50% of radio-attributed cases call after day 30 from first exposure. A 30-day window cuts those cases from your attribution entirely. The result: radio appears to produce fewer cases than it does, which makes it look more expensive than your other channels when you compare cost per case.

Run your radio cost-per-case calculation at 30, 60, and 90 days and watch how the cohort matures. The 30-day number will look discouraging. The 90-day number is the defensible one. If you apply 30-day windows across all channels for consistency, understand that radio will be the most systematically undercounted channel in your portfolio.

How Radio Fits Into Your Full-Channel Comparison

Once you have a cost-per-case number for radio, the comparison is straightforward. Tag every radio-attributed case in your CRM the same way you tag Google, Facebook, TV, billboard, and aggregator cases. Run the same cost-per-case query across all channels. Radio earns a line on the same dashboard—no more “brand awareness budget” exemptions.

For most PI firms, radio lands in the mid-range: more expensive per case than branded search and attorney referrals, less expensive than shared aggregator leads and Facebook Lead Ads. That relative position tells you exactly where radio fits in a budget reallocation conversation.

If your radio cost per case comes in at $4,200 and your aggregator cost per case is $3,800, that is not an automatic reason to cut radio. It is information. Radio builds recall that compounds over time—making your digital ads more effective and referrals easier to close. The cost-per-case number is not the whole picture. It is the starting point for an informed decision, which is exactly what you cannot make without it.

Tracking radio the same way you track every other source is the foundation. RevenueScale's Source Intelligence layerpulls all channel data into a single cost-per-case view, including offline sources like radio, so your budget decisions are based on your actual portfolio—not just the channels with easy digital tracking.

Start with One Station, Then Scale the Framework

If you are running radio across four stations with no attribution infrastructure, do not try to build it all at once. Pick your highest-spend station. Assign a dedicated tracking number this week. Add the radio source tag to your intake dropdown in the same conversation. Run that setup for 90 days and calculate your first cost-per-case number.

That single data point will tell you more about your radio investment than the last year of GRP reports from your stations combined. Once you have one station working, replicating the framework across your full radio buy takes less than a week.

Radio is one of the most powerful brand-building channels in PI marketing. It deserves the same measurement discipline as every other source in your portfolio. Firms that build this infrastructure now can defend their radio budgets—or reallocate them confidently— while competitors are still running on faith and reach reports.

To see what a full-channel cost-per-case view looks like for your firm, book a demoand we will walk you through how RevenueScale connects radio spend to signed cases alongside every other source you manage.