Duplicate purchase event rate after web shop + store dual paths

Dual paths create duplicate purchase events in the MMP. Illustrative duplicate rate using web and app event definitions.
Web shop plus store IAP without an order-id dedupe will double-count payers in F2P LTV.
Definitions
Web purchase events are first-class in PBA attribution rules. Store IAP uses af_purchase (event structure). Nothing in those pages merges the two paths automatically. Near neighbour: web-shop double-count lab (revenue overlap); this article counts events.
Synthetic duplicate rate
| Path | Events |
|---|---|
| Store `af_purchase` | 5,000 |
| Web purchase | 2,200 |
| Shared order IDs | 600 |
| Naive sum | 7,200 |
| Distinct orders | 6,600 |
| Duplicate rate | 8.33% |
Facts vs limits
| Fact | Limit |
|---|---|
| Two event surfaces are documented | Dedup key design is studio BI |
| Synthetic rate is teaching | Not an industry dual-path average |
CSV.


