Less out-of-stock (OOS) situations due to the continuous checking of the shelves,
coupled with automatically triggered replenishment. The exact magnitude of OOS
situations and the resulting losses to retailers and manufacturers cannot be easily
measured since the phenomenon is not recorded; only actual purchases are. Many
studies have tried to estimate the magnitude of OOS; for example the GMA/FMA
[18] estimates 8.2% out of stock situations, costing retailers about 4% of sales,
with a quarter of these incidents resulting from items in the store but not on the
shelf.