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

Say you cut a vendor last quarter because their cost per lead hit $120 — twice what your other source charges. Six months later you learn their cases were settling at $85,000 on average. Your cheaper vendor's cases? $22,000. You made the wrong call with the right data, because you were reading one metric when the decision required three.

Cost per lead. Cost per case. Average settlement value per source. Each answers a different question about the same marketing spend. None tells the full story alone. Here is what each metric actually measures, when each one is the right signal, and how building toward all three changes how you manage vendor relationships and budget.

Cost Per Lead: The Top-of-Funnel Metric

Cost per lead (CPL) is simple: total spend on a source divided by the leads delivered. Pay a vendor $20,000, receive 400 leads — your CPL is $50. It answers one question: how much does it cost to get an initial contact from this source?

What CPL Tells You

• Whether a vendor is generating volume efficiently relative to what you're paying
• Whether CPL is trending up as you scale with a vendor — often a sign of audience saturation
• Early signals on new vendors before you have enough data to calculate cost per case
• Anomalies worth investigating — a sudden CPL spike from a stable vendor usually means their traffic quality or bidding changed

What CPL Does Not Tell You

CPL says nothing about what happens to those leads after they arrive. Two vendors with identical CPL can produce wildly different cost per case numbers. A vendor at $100 per lead with a 15% signed-case conversion rate is worth far more than one at $50 with a 3% rate — even though the first 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 total spend on a source divided by signed cases produced. Pay $20,000 and sign 8 cases — your cost per case is $2,500.

CPC is the most actionable performance metric in PI marketing because it connects spend directly to the outcome your firm actually buys: signed cases. It folds in lead quality implicitly — a vendor with a strong conversion rate produces a lower CPC than one with weak conversion, even when their CPL looks similar.

What CPC Tells You

• The true efficiency of each source at producing signed cases — the core product your firm runs on
• Which vendors justify their price when you look past CPL
• An apples-to-apples comparison across vendors with different pricing structures (per-lead, per-call, flat retainer)
• Where intake may be leaking — good CPL but poor CPC usually signals a conversion problem at intake, not a lead quality problem

What CPC Does Not Tell You

CPC tells you what you paid to sign the case. It does not tell you whether that case was worth signing at that price.

A vendor at $2,500 per case sounds excellent — until you learn those cases settle at $15,000 on average, while another vendor's cases at $4,000 each settle at $75,000. The first vendor's economics are far worse despite the lower CPC. Case value is the missing variable — and that is 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 to calculate — and the most strategically valuable once you have it. It measures the average dollar amount settled for cases that came from a specific lead source.

Not all signed cases are equal. A case from a severe accident with clear liability might settle at $250,000. A minor fender-bender might settle at $8,000. If one vendor consistently routes high-severity cases while another delivers soft-tissue volume, vendor economics look completely different once you factor in what those cases were worth.

What Average Settlement Value Tells You

• Which sources produce the highest-value cases over the full settlement cycle — not just which produce the most cases
• Actual marketing ROI — what you paid per case vs. what those cases returned
• Whether a vendor with a high CPC is actually more efficient when you account for the value they deliver
• Case mix trends — are cases from a specific source trending higher or lower in value over time?

The Challenge With This Metric

PI cases take 6 to 18 months to settle. To get statistically meaningful data, you need to hold source attribution through the full settlement lifecycle — and you need enough settled cases per source for a reliable sample.

For a firm settling 10 to 15 cases per month from a vendor, expect 6 to 12 months before averages stabilize. Early data skews low because the fastest-settling cases are typically lower-value soft-tissue matters. Higher-value cases with surgery, disputes, or litigation take longer to resolve — and longer to reach your numbers.

That is not a reason to skip the metric. It is a reason to start collecting consistently now, so the data becomes reliable over time.

A Practical Illustration: Three Vendors, Three Metrics

Three vendors. Same $30,000 budget. One month. Here is what the data looks like at each layer of analysis:

Rank by cost per lead: Vendor B wins. Vendor C looks like the worst investment in the portfolio.

Rank by cost per case: Vendor A takes the top spot. Vendor C still looks weakest.

Rank by revenue multiple once settlement data enters: Vendor C leads at 28.5x. The vendor with the worst CPL and worst CPC delivers the best return.

These patterns are real, not manufactured. The vendor who sends fewer leads at a higher price but routes higher-severity cases is frequently your best source on a returns basis — and the first one cut when firms rely on CPL or CPC alone.

Using All Three Together

The goal is not to pick the right metric — it is to know which metric is most actionable given your data maturity and the decision in front of you.

• CPL for early signals and ongoing monitoring. With a new vendor, CPL is the best signal available until case data accumulates. For established vendors, a CPL spike is your fastest indicator that something changed in their traffic or targeting.
• CPC for vendor budget allocation. When you are deciding whether to increase, hold, or cut a vendor, cost per case cuts through CPL noise and gives you the real efficiency number. It is the primary metric for monthly and quarterly budget reviews.
• Settlement value per source for long-term portfolio strategy. Once you have 12 or more months of settled case data by source, this metric reframes your entire vendor mix. Vendors that looked expensive on CPC may be your best producers. Vendors that looked efficient may be filling your pipeline with low-value cases that consume resources without proportionate return.

Firms that build toward all three — in that sequence — develop a marketing analytics capability that is hard to replicate. They know not just what their cases cost, but what those cases are worth. That is the complete picture. And it is the picture that changes how you think about vendor relationships, budget calls, and what “good” actually means for a lead source.