Simulation Modeling
Definition
Simulation modeling builds a computer model of a supply chain process or network and runs it many times with realistic variability to test how designs and policies perform before committing real money.
In Practice
Unlike optimization, which finds a single best answer to a simplified problem, simulation replays messy reality: random demand, variable lead times, machine breakdowns, labor shifts. Discrete-event simulation is the standard technique — the model steps through individual events (an order arrives, a truck docks, a picker finishes) and accumulates statistics over thousands of replications.
Practitioners reach for simulation when averages lie: an automation design that works on average volume may collapse on peak-day surges, and only simulation exposes the queue that forms at the packing stations at 2 p.m. It is also the honest way to test inventory policies against fat-tailed demand before changing them network-wide.
Example: before signing off a new DC design, a retailer simulates Black Friday volume through the proposed conveyor and sorter layout, discovering a merge point that would jam — fixed on screen for nothing instead of in steel for millions.
Related Terms
A digital twin is a living virtual model of a physical supply chain — its nodes, flows, inventories, and constraints — kept in sync with real data so teams can test decisions virtually before making them.
Prescriptive AnalyticsPrescriptive analytics goes beyond predicting outcomes to recommending or automating the best action, typically using optimization or simulation to weigh costs, constraints, and service goals.
Advanced Planning and Scheduling (APS)Advanced Planning and Scheduling (APS) software creates feasible, optimized production and supply plans by considering material availability, machine capacity, and demand priorities simultaneously — something basic MRP cannot do.