When there is insufficient stock to meet a specific customer order, a commo
n assumption is that the remaining stock will be used to satisfy the order
partially while the balance of the order is backordered or lost - this is t
he 'partial backorder' or 'partial lost sales' assumption. In this paper we
consider what happens when the nature of the demand process is such that o
rders must be met in full or not at all - this is the 'all-or-nothing' dema
nd assumption. We concentrate, for the purpose of illustration, on the cont
ext of a continuous review model, with a Poisson customer arrival rate, wit
h a fixed lead time and for which not more than one replenishment order may
be outstanding at any time. (C) 2001 Elsevier Science B.V. All rights rese
rved.