The Outlier Lab

Friction and Customer Experience Tradeoffs

How to price fraud friction: total cost of fraud, insult rates, the cost of good customers declined or delayed, choosing the cheapest effective action, and governing the friction budget.

Core components

Total cost of fraud

Total cost = fraud losses
           + operational cost (review, investigation, disputes, support contacts)
           + good-customer cost (declined revenue, delay cost, churn, lifetime-value loss)
           + compliance and partner cost (fines, monitoring programs, partner fees)

The objective is to minimize total cost, not losses alone. A control that cuts losses by $100K and costs $300K in good-customer friction is a bad control.

The friction ladder

Choose the lightest action that achieves the needed risk reduction:

ActionGood-customer costFraud-stopping powerBest for
Invisible (passive scoring, silent monitoring)NoneDetection onlyBaseline everywhere
Soft friction (warnings, confirmations, payee name check)Very lowModerate for scams; low for ATOVictim-authorized flows (see Payee Confirmation and Payment Friction, Customer Education and Scam Warnings)
Step-up (OTP, passkey, biometric re-auth)Low to moderateHigh for ATO if the factor is strongRisky sessions, account changes, money-out (see Risk-Based Authentication and Step-Up)
Delay / holdModerate (time cost)High for reversible-funding fraudFunding before finality, new payout destinations (see Funds Availability Holds)
LimitLow to moderateCaps exposureNew accounts, new instruments (see Velocity and Exposure Limits)
Manual reviewModerate to high (latency)High if analysts are goodAmbiguous, high-value cases
DeclineHighComplete for that transactionHigh-confidence fraud
Account action (restrict, close)Very highHighConfirmed bad actors

Measuring good-customer cost

MeasureDefinitionHow to get it
Insult rate / false positive rateShare of good customers who hit a controlLabels plus holdouts; QA samples of declines (see Fraud QA Program)
False positive ratioGood customers actioned per fraudster actionedLabels
Step-up failure and abandonmentShare of good customers who fail or abandon a challengeFunnel analytics
Hold costValue delayed × duration × cost per dollar-day (opportunity cost, complaint risk)Product analytics
Post-friction churnRetention of customers who hit friction vs matched controlsExperiment or matched cohort analysis
Contact rateSupport contacts per 1,000 actioned customersSupport data (see Customer Contact Signals)
Complaint rateFormal complaints, regulator complaintsComplaints data

Use matched cohorts or experiments to estimate churn impact. Simple before/after comparisons are confounded by everything else going on (see Experimentation and Champion-Challenger).

How to build it

Decline economics: a worked example

Segment-aware friction

The same control has very different costs by segment:

  • Tenure. Friction on a 5-year customer with clean history costs far more (high LTV, high trust, low prior risk) than on a 1-day-old account. See Customer Tenure and History.
  • Value tier. High-value customers churn harder and complain louder.
  • Vulnerability. Older or vulnerable customers may need more protective friction for scams, applied with care. See Elder Financial Exploitation, Trusted Contact and Senior Investor Holds.
  • Channel and context. A step-up during a session that's already authenticated with a passkey is cheaper than an SMS OTP after a password login.

Governing the friction budget

  • Set a friction budget per money path alongside the loss appetite: maximum insult rate, maximum hold rate, maximum step-up rate. Agree on both with the business owner (see Fraud Operating Model).
  • Require friction estimates in every strategy proposal (see Fraud Strategy Lifecycle).
  • Review the friction leaders quarterly. These are the rules and models affecting the most good customers (see Rule Governance and Change Management).
  • Revisit after attacks. Friction added during an incident should be re-justified once it's over.
  • Track friction "debt", the cumulative good-customer impact of all live controls, trended over time.

Who owns what

ActivityFraud strategyProductCX / SupportFinanceAnalytics
Friction budgetRA (jointly with exec risk owner)CCC
Friction estimates per strategyA/RCCR
Good-customer cost modelCCCAR
Friction leader reviewA/RCCR
Customer messaging for frictionCA/RR

Artifacts and templates

Friction impact statement (for every strategy proposal)

FieldValue
Action typeDecline / hold / step-up / review / limit / warning
Good customers affected per month
Segments most affected
Expected step-up pass rate / hold duration
Estimated good-customer cost
Lighter alternative considered
Why the chosen action

Friction review checklist (quarterly)

  • Top 10 friction-generating controls listed, with good-customer counts
  • Each one: is a lighter action viable?
  • Emergency friction from past incidents removed or re-justified
  • Friction by segment: high-tenure, high-value and vulnerable customers
  • Complaint and contact themes linked to specific controls
  • Holdout results: is friction buying real loss reduction?

Metrics

MetricDirection
Total cost of fraud (bps of volume)Down
Insult rate by money path and segmentDown at equal or lower loss
False positive ratioDown
Step-up abandonment rateDown
Median hold duration and share of value heldDown where loss allows
Friction-related contacts and complaintsDown
Approval rate on good customers (estimated)Up

Pitfalls

  • Counting only losses. This is the most common failure, and it produces steadily rising friction.
  • Average insult rate hiding a segment problem. 1% overall can be 10% for a valuable segment.
  • Assuming step-up is free. SMS OTP failure, delivery delays and abandonment are real costs. Phishing-resistant authenticators lower them (see Passkeys and Phishing-Resistant Authentication).
  • Hold creep. Holds introduced for an attack become permanent.
  • Detailed decline reasons to customers. Tell customers clearly that a control applied, but keep explanations general so attackers can't learn which signal tripped.
  • No counterfactual. Without holdouts you can't prove friction is buying anything.

Sources and further reading