Learn · Component 2 - Tools and calculators (/tools/)
tier threshold modeller
Model tier thresholds by connecting qualifying behaviour to reward cost, member movement, and operational complexity. Test the boundary cases before publishing a status rule.
## The mechanism
Define the qualifying event, value change, owner, correction path, and member explanation. Keep eligibility, liability, fulfilment, consent, and reversal as separate rules. The operating control must be testable from the ledger.
## Worked example
Illustrative arithmetic: a member has 80 qualifying points and the next tier begins at 100 points, leaving 20 points. If each purchase earns 10 points, 2 purchases close the gap.
## Do it
State the rule in one sentence. Map the event that starts it, the event that changes value, the exception path, and the review action. Test ordinary, cancelled, duplicated, and disputed cases before release.
## Common mistakes
- Measuring activity instead of the target behaviour. Name the counterfactual. - Treating face value as operator cost. Price fulfilment and correction. - Hiding exclusions or expiry. Put the boundary beside the decision. - Automating an undefined rule. Resolve ownership before implementation.