THE RESULT
What the data shows
The largest computed metric is 0.5944 for 2010-12; the smallest is 0.3838 for 2011-05. Metric: rate (90-day repeat share).
First observed is not necessarily first-ever purchase. Simultaneous invoices do not count as a later purchase. Wilson intervals assume independent customers.
| month | events | n | rate | wilson lower | wilson upper |
|---|---|---|---|---|---|
| 2010-12 | 526 | 885 | 0.5944 | 0.5617 | 0.6262 |
| 2011-01 | 202 | 417 | 0.4844 | 0.4368 | 0.5323 |
| 2011-02 | 167 | 380 | 0.4395 | 0.3904 | 0.4897 |
| 2011-03 | 189 | 452 | 0.4181 | 0.3735 | 0.4641 |
| 2011-04 | 125 | 300 | 0.4167 | 0.3623 | 0.4732 |
| 2011-05 | 109 | 284 | 0.3838 | 0.3292 | 0.4416 |
| 2011-06 | 93 | 242 | 0.3843 | 0.3253 | 0.4469 |
| 2011-07 | 81 | 188 | 0.4309 | 0.3621 | 0.5023 |
| 2011-08 | 78 | 169 | 0.4615 | 0.3881 | 0.5367 |
| 2011-09 | 31 | 53 | 0.5849 | 0.4509 | 0.7074 |
THE METHOD
From source to answer
First-observed invoices and a fixed 90-day eligibility window.
The Python source exposes this study’s transformations. The complete project download includes shared preparation and evaluation routines.
THE NEXT DECISION
What follows from the finding
Compare cohorts with equal observation time before testing acquisition or onboarding changes.
Where the conclusion stops
Historical invoice lines; credits are not reliably matched to original sales. Gross purchases are not profit. Unidentified customers cannot support customer-level conclusions. Exact repeated lines remain unless the study explicitly compares removal.
Related studies may reuse observations or holdouts. These are historical analyses; associations and backtests do not demonstrate commercial impact. Further model tuning needs new, untouched evaluation data.