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cheaper alternatives to a program
Define the rule, cost, member promise, and operational control before launch. Use observed behaviour for thresholds and test the full liability case.
The design decision for cheaper alternatives to a program is economic and operational. Define the behaviour, cost, ledger event, and member promise before launch.
## The mechanism useful design has a clear trigger, measurable threshold, redemption or control path, and owner. Keep qualification, liability, reversals, consent, and expiry as separate rules.
## Worked example is illustrative arithmetic. A member earns 2 points per dollar on 400 dollars of spend, creating 800 points. At 1 cent per point, the balance represents 8 dollars. A change to 3 points creates 1,200 points worth 12 dollars, increasing visible value by 4 dollars.
## Do it the rule in one sentence. Test the qualifying event, member explanation, operator cost, reversal, and exit condition. Compare the result with a holdout or simpler alternative.
## Common mistakes
- Confusing activity with changed behaviour. Measure the counterfactual. - Treating face value as cost. Use operator cost. - Hiding the rule. Publish thresholds and notices. - Relying on breakage. Test full redemption.