Bestellfunktion

Bestellfunktion is a term used in inventory management and supply chain theory to describe a rule that determines the quantity of an order to place based on the current state of the system. In practice, the function maps the present stock level and possibly other state variables to a requested order quantity. The goal is to balance ordering, holding, and shortage costs while ensuring adequate service levels.

A typical form is the order-up-to policy, also called base-stock policy. Here the Bestellfunktion O(x) orders enough to raise the inventory to a target level S, so O(x) = max(0, S − x), where x is the on-hand inventory. In this setting, orders are triggered whenever the stock falls below the target, and the quantity depends on the gap to S. Another common form is the (s, S) policy: O(x) = max(0, S − x) if x ≤ s, otherwise O(x) = 0. A fixed-quantity policy, O(x) = Q, orders are always of a constant size when an ordering decision is made.

These functions are used in continuous-review and periodic-review systems and are often derived from dynamic programming or optimization models that account for lead time, stochastic demand, and cost structures. The classical Economic Order Quantity (EOQ) framework yields a fixed-order quantity under certain assumptions, while real-world applications may employ more complex or state-dependent policies.

Limitations include uncertainty in demand, lead times, and supply constraints. The Bestellfunktion remains a central concept for formalizing decision rules in inventory control and operations research.