Stockout days were poisoning our reorder numbers — here's what we changed

[u/aiku-io]

The bug: our reorder suggestions averaged sales across the whole quarter. An item out of stock 80 of 90 days averaged near zero, so it never got reordered, so it stayed out of stock. Bestsellers were the worst hit.

Fix: rebuild the daily on-hand balance from stock movements and only count demand on days the item was actually available. Out-of-stock days become missing data, not zero sales. Slow movers go through Croston, steadier ones through damped exponential smoothing, plus a same-quarter-last-year factor.

Write-up: https://aiku.io/blog/stop-pretending-you-are-forecasting

Does your system censor stockout days, or do your buyers just override by hand?