Worked case · Failure and stress · 12 figures

Protection and access cost

Measure protection and customer cost

Figure 01 / 12

The evaluated population

The evaluated population — Protection and access cost. Count; one closed observation cohort. Exact values are in the figure data below.
Count; one closed observation cohort

The cohort contains 42,000 account access attempts, of which 168 have the defined synthetic outcome: Synthetic takeover loss. The outcome is known by construction here. In production, label uncertainty and selection must be recorded separately.

Figure data and text version
OutcomeCount
Synthetic takeover loss168
Other labeled outcomes41,832

A takeover control can reduce harmful activity while making legitimate recovery difficult. The operating point needs both loss and customer-impact evidence.

Aggressive flags are reported as prevented loss without checking legitimate customer outcomes.

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 2,382 of 42,000 account access attempts. Of those flags, 81 meet the synthetic target, giving 3.4% precision. It misses 87 target events. Under the stated cost assumptions, residual loss and operating friction total $186,372. 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
population42,000
prevalence0.004
severity1,500
margin16
reviewCost8
Calculated valueResult
population42,000
positive168
negative41,832
tp81
fp2,301
fn87
tn39,531
loss130,500
severity1,500
precision3.4
recall48.21
Figure 02 / 12

Four outcomes of the rule

Four outcomes of the rule — Protection and access cost. 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 81 synthetic positives and 2,301 negatives. It misses 87 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 takeover loss8187
Other outcome2,30139,531
Figure 03 / 12

Three rates with different denominators

Three rates with different denominators — Protection and access cost. Rates within this cohort. Exact values are in the figure data below.
Rates within this cohort

Precision is 3.4%, recall is 48.21%, and the false-positive rate is 5.5%. 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
Precision812,3823.4%
Recall8116848.21%
False-positive rate2,30141,8325.5%
Figure 04 / 12

Precision changes with prevalence

Precision changes with prevalence — Protection and access cost. Percent; fixed conditional detection rates. Exact values are in the figure data below.
Percent; fixed conditional detection rates

This sensitivity plot holds recall at 48% and false-positive rate at 5.5%, 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%0.87
0.5%4.2
1%8.1
2%15.12
5%31.48
10%49.23
Figure 05 / 12

The threshold trade-off

The threshold trade-off — Protection and access cost. 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 11656,275
Band 21583,347
Band 31441,464
Band 4121502
Band 584167
Band 64242
Figure 06 / 12

A transparent loss-and-friction calculation

A transparent loss-and-friction calculation — Protection and access cost. 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 $1500 severity per missed synthetic positive, residual loss is $130,500. Review costs $19,056; lost contribution on false alarms is $36,816. 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 loss130,500
Review cost19,056
False-alarm contribution36,816
Figure 07 / 12

Observed outcomes mature over time

Observed outcomes mature over time — Protection and access cost. Count; final outcome fixed. Exact values are in the figure data below.
Count; final outcome fixed

The final synthetic positive count is 168. 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
130
359
7101
14138
30168
Figure 08 / 12

Review demand and available capacity

Review demand and available capacity — Protection and access cost. Items in the cohort window. Exact values are in the figure data below.
Items in the cohort window

The flag count is 2,382. The comparison capacity is an illustrative 1,680 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 review2,382
Available capacity1,680
Excess demand702
Figure 09 / 12

A feature is an observation with provenance

A feature is an observation with provenance — Protection and access cost. Illustrative data contract. Exact values are in the figure data below.
Illustrative data contract

This evidence contract supports measure protection and customer cost. 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_refProtection and access costSubject of this case
event_time2026-09-18T09:00:00ZWhen the event occurred
received_time2026-09-18T09:00:02ZWhen the system learned it
signal_statuslateEvidence quality, not an outcome
label_definitionSynthetic takeover lossThe target used in these calculations
Figure 10 / 12

Missing evidence changes the observed population

Missing evidence changes the observed population — Protection and access cost. 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 evidence36,9605,040
Activity history30,24011,760
Context signal25,20016,800
Figure 11 / 12

Evidence, score, and action remain separate

Evidence, score, and action remain separate — Protection and access cost. Decision lifecycle. Exact values are in the figure data below.
Decision lifecycle

The policy can use measure protection and customer cost 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
ObserveProtection and access cost: evidence as of the decision time
EvaluateRule flags 2,382 of 42,000 account access 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 — Protection and access cost. 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 target81 known synthetic positives flaggedProduction labels may be delayed or wrong
Prevented lossAssumed 121,500 USDRequires an intervention-effect assumption
Customer impact2301 synthetic negatives flaggedNot every flag causes abandonment
Unobserved alternativeOutcome without the actionNeeds a valid evaluation design

Connect the result to the system

Measure mature labels, false alarms, recovery delay, and the effect of the actual intervention.

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. NIST SP 800-63B-4: authentication
  2. NIST SP 800-63A-4: identity proofing