ORIGINAL COMPANY-CONTEXT PRACTICE
Calculate dispute rates with matching denominators
Original practice scenario: A hypothetical merchant dashboard divides disputes filed this month by transactions processed this month. Explain why the ratio can mislead and propose a cohort-based query.
Written for independent practice using company context; this is not a verified question from a company interview.
A REASONED APPROACH
Model answer.
Match dispute outcomes to the transaction population that could generate them. Filing-month counts can refer to old purchases while the denominator contains unrelated new activity.
Work through it
- Link each dispute to its original transaction identity and merchant, deduplicating repeated case updates and distinguishing multiple valid dispute categories if the metric requires them.
- Create transaction-date cohorts, define an observation maturity window, and count eligible transactions with at least one qualifying dispute under that rule.
- Report cohort size, matured coverage and uncertainty alongside the rate, separating unresolved linkage and merchants with insufficient history.
Tradeoffs to discuss
- Mature cohorts are comparable but lag current operations; a separate filing-volume measure can support staffing without pretending to be a transaction risk rate.
Common pitfalls
- Joining every case update to transactions can multiply both amounts and counts.
- Changing dispute eligibility or observation windows requires a metric version, not a silent dashboard edit.