Worked case · Controlled response · 12 figures

Approval-rate denominator

Keep denominators honest

Figure 01 / 12

The evaluated population

The evaluated population — Approval-rate denominator. Count; one closed observation cohort. Exact values are in the figure data below.
Count; one closed observation cohort

The cohort contains 32,000 card attempts, of which 384 have the defined synthetic outcome: Synthetic fraud outcome. The outcome is known by construction here. In production, label uncertainty and selection must be recorded separately.

Figure data and text version
OutcomeCount
Synthetic fraud outcome384
Other labeled outcomes31,616

A card dashboard mixes attempts, approved payments, and value-weighted loss. The resulting percentage appears precise while its population changes between reports.

Publish numerator, denominator, cohort, time basis, and label definition together.

All amounts, rates, capacity limits, and outcomes in this case are synthetic. The three conditions are separate assumptions for comparison. A better result in the response condition is not measured proof that the proposed control causes that improvement. The figures expose the calculation and its limits; a real deployment needs its own evidence.

Read the result

The rule flags 709 of 32,000 card attempts. Of those flags, 330 meet the synthetic target, giving 46.54% precision. It misses 54 target events. Under the stated cost assumptions, residual loss and operating friction total $9,212. The important result is the connection between the population, action, capacity, and outcome—not one isolated score.

Model inputs and calculated values

Inputs below are the case-specific values. Each figure states the condition-specific assumptions and units used in its calculation. Calculated values are rounded for display.

InputValue
population32,000
prevalence0.012
severity90
margin4
Calculated valueResult
population32,000
positive384
negative31,616
tp330
fp379
fn54
tn31,237
loss4,860
severity90
precision46.54
recall85.94
Figure 02 / 12

Four outcomes of the rule

Four outcomes of the rule — Approval-rate denominator. Counts; rows are actual labels, columns are actions. Exact values are in the figure data below.
Counts; rows are actual labels, columns are actions

The rule flags 330 synthetic positives and 379 negatives. It misses 54 positives. A flagged item is a decision to intervene; it is not proof of fraud, a legal prohibition, or any other real-world conclusion.

Figure data and text version
Known outcomeFlaggedNot flagged
Synthetic fraud outcome33054
Other outcome37931,237
Figure 03 / 12

Three rates with different denominators

Three rates with different denominators — Approval-rate denominator. Rates within this cohort. Exact values are in the figure data below.
Rates within this cohort

Precision is 46.54%, recall is 85.94%, and the false-positive rate is 1.2%. Changing the denominator changes the meaning. This record keeps each numerator attached to the population from which it came.

Figure data and text version
MetricNumeratorDenominatorResult
Precision33070946.54%
Recall33038485.94%
False-positive rate37931,6161.2%
Figure 04 / 12

Precision changes with prevalence

Precision changes with prevalence — Approval-rate denominator. Percent; fixed conditional detection rates. Exact values are in the figure data below.
Percent; fixed conditional detection rates

This sensitivity plot holds recall at 86% and false-positive rate at 1.2%, then changes prevalence. It is an algebraic comparison, not a forecast. Even unchanged detection quality can produce a very different review queue when the base rate changes. Horizontal positions are the labeled observations or scenarios; equal spacing does not imply equal numerical increments.

Figure data and text version
Assumed prevalencePrecision %
0.1%6.69
0.5%26.48
1%41.99
2%59.39
5%79.04
10%88.84
Figure 05 / 12

The threshold trade-off

The threshold trade-off — Approval-rate denominator. Count in the same cohort. Exact values are in the figure data below.
Count in the same cohort

Six illustrative score bands use a stated pair of detection rates. Lower sensitivity can reduce false alarms but miss more target events. These points do not come from a trained model and do not establish the best operating threshold. Horizontal positions are the labeled observations or scenarios; equal spacing does not imply equal numerical increments.

Figure data and text version
Score bandTrue positivesFalse positives
Band 13764,742
Band 23612,529
Band 33301,107
Band 4276379
Band 5192126
Band 69632
Figure 06 / 12

A transparent loss-and-friction calculation

A transparent loss-and-friction calculation — Approval-rate denominator. Illustrative USD; expected cost under stated intervention assumptions. Exact values are in the figure data below.
Illustrative USD; expected cost under stated intervention assumptions

At $90 severity per missed synthetic positive, residual loss is $4,860. Review costs $2,836; lost contribution on false alarms is $1,516. The calculation assumes intervention prevents all flagged-positive loss and each false alarm loses the stated contribution. Relax those assumptions before applying it to a real policy.

Figure data and text version
Cost componentUSD
Missed-positive loss4,860
Review cost2,836
False-alarm contribution1,516
Figure 07 / 12

Observed outcomes mature over time

Observed outcomes mature over time — Approval-rate denominator. Count; final outcome fixed. Exact values are in the figure data below.
Count; final outcome fixed

The final synthetic positive count is 384. Earlier observations reveal only a stated fraction. Comparing a day-1 cohort with a day-30 cohort would confuse label age with control quality. This curve models observation delay only; it does not change the final outcome. Horizontal positions are the labeled observations or scenarios; equal spacing does not imply equal numerical increments.

Figure data and text version
Days after eventObserved positives
169
3134
7230
14315
30384
Figure 08 / 12

Review demand and available capacity

Review demand and available capacity — Approval-rate denominator. Items in the cohort window. Exact values are in the figure data below.
Items in the cohort window

The flag count is 709. The comparison capacity is an illustrative 1,280 reviews per cohort window. A mathematical rule can be coherent while its resulting workload exceeds the operating team’s capacity. Capacity is not permission to ignore an applicable mandatory control.

Figure data and text version
Queue measureItems
Flagged for review709
Available capacity1,280
Excess demand0
Figure 09 / 12

A feature is an observation with provenance

A feature is an observation with provenance — Approval-rate denominator. Illustrative data contract. Exact values are in the figure data below.
Illustrative data contract

This evidence contract supports keep denominators honest. A value needs its event time, arrival time, scope, and source. Keeping unavailable evidence distinct from a measured zero prevents an outage from becoming a falsely reassuring feature.

Figure data and text version
FieldExampleMeaning
entity_refApproval-rate denominatorSubject of this case
event_time2026-09-18T09:00:00ZWhen the event occurred
received_time2026-09-18T09:00:02ZWhen the system learned it
signal_statusrepairedEvidence quality, not an outcome
label_definitionSynthetic fraud outcomeThe target used in these calculations
Figure 10 / 12

Missing evidence changes the observed population

Missing evidence changes the observed population — Approval-rate denominator. Count; each row is the same cohort. Exact values are in the figure data below.
Count; each row is the same cohort

The cells show an explicitly constructed completeness profile for three signal groups. The stress condition removes more history and device evidence. Missingness does not prove the target outcome; it changes what the decision process knows.

Figure data and text version
Signal groupAvailableMissing
Identity evidence31,840160
Activity history31,520480
Context signal31,040960
Figure 11 / 12

Evidence, score, and action remain separate

Evidence, score, and action remain separate — Approval-rate denominator. Decision lifecycle. Exact values are in the figure data below.
Decision lifecycle

The policy can use keep denominators honest only within its approved scope. The action record must retain which evidence was available, which model or rule ran, and which action was actually applied. The final action can differ from the score recommendation when a separate constraint applies.

Figure data and text version
StageRecord
ObserveApproval-rate denominator: evidence as of the decision time
EvaluateRule flags 709 of 32,000 card attempts
ApplyRecord action, reason, owner, and expiry
ReconcileJoin the action to later outcomes without overwriting history
Figure 12 / 12

What the result cannot establish

What the result cannot establish — Approval-rate denominator. Interpretation boundary. Exact values are in the figure data below.
Interpretation boundary

Observed classifications do not reveal every counterfactual. The synthetic labels make arithmetic possible, but production decline data is selected by prior policy. Keep measured outcomes, assumed prevention, and unknown alternatives separate when reporting impact.

Figure data and text version
ClaimEvidence in this caseLimit
Detected target330 known synthetic positives flaggedProduction labels may be delayed or wrong
Prevented lossAssumed 29,700 USDRequires an intervention-effect assumption
Customer impact379 synthetic negatives flaggedNot every flag causes abandonment
Unobserved alternativeOutcome without the actionNeeds a valid evaluation design

Connect the result to the system

Publish numerator, denominator, cohort, time basis, and label definition together.

Check the population, evidence, permitted action, and actual effect together. A balanced calculation can still use the wrong population; a successful response can still leave an unknown financial outcome. The case’s numerical result applies only to its stated assumptions.

Sources and further reading

The chapter sources support the concepts and scope. They do not prescribe the synthetic model rates.

  1. Stripe: PaymentIntent lifecycle (provider example)
  2. Stripe: how disputes work (provider example)
  3. PCI Security Standards Council: PCI DSS