Customer analytics: segmentation and retention
1.07 million transactions, UK wholesale, 2009 to 2011

I expected retention to fall away steadily after acquisition. It did not. Most cohorts retained better in month two or three than in month one, because retailers reorder on their own stock cycle.
A standard 30 day churn rule would have flagged healthy accounts as lost. The analysis also found the source table was not a transactions table at all, but an operational log holding four different record types under one schema.
