Cost Per Lead vs. Cost Per Case vs. Average Settlement Per Source: Which Metric Wins?

Cost per lead. Cost per case. Average settlement value per source. Three metrics. Three different windows into the same marketing investment. None of them tells the whole story alone — and using only one while ignoring the others leads to budget decisions that look right on one dimension and wrong on another.

Here is what each metric actually measures, when each one is the most useful signal, and why the complete picture requires all three working together.

Cost Per Lead: The Top-of-Funnel Metric

Cost per lead (CPL) is your total spend on a source divided by the number of leads that source delivered. If you paid a vendor $20,000 and they sent 400 leads, your CPL is $50.

CPL answers one specific question: how much does it cost to get an initial contact from this source?

What CPL Tells You

• Whether a vendor is efficient at generating initial volume relative to what you're paying
• Whether your spend with a vendor is buying more or fewer leads over time (is CPL trending up as you scale?)
• Early signals on new vendors before you have enough data to calculate cost per case
• Anomalies worth investigating — a sudden jump in CPL from a stable vendor often signals a change in their traffic quality or bidding strategy

What CPL Does Not Tell You

CPL says nothing about what happens to those leads after they arrive. Two vendors can have identical CPL numbers and produce completely different cost per case numbers if their lead quality differs. A vendor charging $100 per lead with a 15% conversion rate to signed cases is dramatically more valuable than a vendor charging $50 per lead with a 3% conversion rate — even though the first one looks twice as expensive at the top of the funnel.

CPL is an input metric. It measures efficiency at the door, not outcomes inside the firm.

Cost Per Case: The Middle-Funnel Metric

Cost per case (CPC) is your total spend on a source divided by the number of signed cases that source produced. If you paid $20,000 and got 8 signed cases, your cost per case is $2,500.

Cost per case is the most commonly cited “real” performance metric for PI marketing — and for good reason. It connects spend directly to the outcome your firm is actually buying: signed cases. It accounts for lead quality by incorporating conversion rate implicitly. A vendor with a high conversion rate produces a lower cost per case than one with a low conversion rate, even if their CPL is similar.

What CPC Tells You

• The true efficiency of each marketing source at producing the core product your firm runs on: signed cases
• Which vendors are worth their price when you look past CPL
• A comparable apples-to-apples metric for vendors with very different pricing structures (per-lead, per-call, flat retainer)
• Where your intake funnel may be leaking — a vendor with good CPL but poor CPC often signals an intake conversion problem, not a lead quality problem

What CPC Does Not Tell You

Cost per case tells you how much you paid to sign the case. It does not tell you whether that case was worth signing at that price.

A vendor producing cases at $2,500 each sounds excellent — until you learn that those cases consistently settle at $15,000 while another vendor's cases at $4,000 each settle at $75,000. The first vendor's economics are actually far worse, even though their CPC is lower. Cost per case ignores case value — which is exactly what average settlement value per source captures.

Average Settlement Value Per Source: The Outcome Metric

Average settlement value per source is the hardest of the three metrics to calculate — and the most strategically valuable when you have it. It measures the average dollar amount settled for cases that originated from a specific lead source.

This metric exists because not all signed cases are equal. A signed case from a severe accident with clear liability might settle at $250,000. A signed case from a minor fender-bender might settle at $8,000. If one vendor consistently produces severe, high-value cases while another produces minor soft-tissue cases, the vendor economics look completely different when you account for settlement value.

What Average Settlement Value Tells You

• Which lead sources produce the highest-value cases over the full settlement cycle
• The actual return on marketing investment — not just what you paid for cases, but what those cases were worth
• Whether a vendor with a high cost per case is actually more efficient when you account for the value they deliver
• Case mix trends — are the cases from a specific source getting higher or lower in average value over time?

The Challenge With This Metric

Personal injury cases take 6 to 18 months to settle. If you want average settlement value data that is statistically meaningful, you need to maintain source attribution through the entire settlement lifecycle — and you need enough settled cases per source to have a reliable sample.

For a firm settling 10 to 15 cases per month from a vendor, you need 6 to 12 months of settlement data before averages stabilize. Early data can be misleading because it reflects only the fastest-settling cases, which tend to be lower-value soft-tissue cases that settle quickly. Higher-value cases with disputes, surgery, or litigation take longer and hit the data later.

This is not a reason to ignore the metric — it is a reason to understand its limitations and to collect the data consistently so that it becomes reliable over time.

A Practical Illustration: Three Vendors, Three Metrics

Consider three vendors running simultaneously for one month:

Ranking by cost per lead: Vendor B, Vendor A, Vendor C. Vendor B looks best.

Ranking by cost per case: Vendor A, Vendor B, Vendor C. Now Vendor A looks best.

Ranking by revenue multiple when settlement data is included: Vendor C, Vendor B, Vendor A. The vendor with the worst CPL and worst CPC produces the best return.

This is not a manufactured example. These patterns are real. The “expensive” vendor who sends fewer leads but routes higher-severity cases is frequently the most efficient source on a return basis — and the least appreciated when firms only look at CPL or CPC.

Using All Three Together

The right approach is not to pick a single metric — it is to understand which metric is most actionable given your data maturity and what decision you're making.

• Use CPL for early signals and ongoing monitoring. When you're evaluating a new vendor, CPL is the best signal you have until case data accumulates. For established vendors, CPL anomalies are the fastest indicator that something changed.
• Use CPC for vendor budget allocation decisions.When you're deciding whether to increase, maintain, or cut a vendor, cost per case is the metric that tells you the truth about their efficiency. It is the most actionable metric for monthly or quarterly budget reviews.
• Use average settlement value per source for long-term vendor strategy. Once you have 12 or more months of settled case data by source, settlement value per source reframes your vendor portfolio entirely. Vendors that looked expensive on CPC may turn out to be your best producers. Vendors that looked efficient on CPC may be producing low-value cases that consume firm resources without generating proportionate revenue.

The firms that build toward all three metrics — in that sequence — end up with a marketing analytics capability that is genuinely difficult to replicate. They know not just what their cases cost, but what they are worth. That is the complete picture. And it is the picture that changes how you think about vendor relationships, budget allocation, and the definition of a “good” lead source.