Cost per signed case: formulas and bases

Cost per signed case is what the marketing cost, divided by the signed cases it can be matched to. Every figure carries its basis (cohort or signing date) and its version, and none is shown for a segment with fewer than 5 attributable signed cases.

The cost metrics

“Media” means what the platforms billed the firm for the channels in the segment, in the period.

Two bases

• Cohort basis, for decisions. Signed cases from leads created in the period, divided by the period’s cost. It ties each case to the spend that produced it, and stays provisional until the cohort matures.
• Signing-date basis, for reconciliation. Cases signed in the period, whatever their lead date. This is what the firm’s records count, so the weekly check uses it.

Headline figures show a rolling 12-week cost per signed case on the signing-date basis. Budget decisions use the cohort basis.

Lag and maturity

• Signing lag: signed date minus lead time, in days, reported as the median and the 80th percentile, by case type and language.
• Cohort maturity: the share of a cohort’s eventual signings that have usually landed by its age, on the firm’s trailing 12-month lag curve. Below 90% it is “provisional”; at 90% or more, “mature”.
• Signed-case rate: signed cases ÷ leads in the same cohort, shown at weeks 1, 2, 4 and 8 and to date.

Blended, marginal and incremental

• Blended: total cost ÷ total attributable signed cases. It describes the average dollar.
• Marginal: the change in cost ÷ the change in signed cases between two spend levels, measured by a step test or estimated from a forecast’s response curve, always with an interval. A budget rises only while marginal cost per signed case stays below the firm’s target and intake has capacity.
• Incremental: the change in media a test made ÷ the incremental signed cases it produced, with its interval (incrementality).

A worked example (ILLUSTRATIVE)

ILLUSTRATIVE, not a client: a channel’s media is $40,000 in a 12-week window, and 10 signed cases on the signing-date basis match it. Media cost per signed case is $4,000. If the same window’s cohort has only reached 70% maturity, its cohort-basis figure is marked “provisional” and may fall as late signings land.

Cite as: The Probative Standard v1.0, Cost per signed case. Last reviewed October 24, 2026, by the Probative editorial team.