Input or exogenous variables

These are variables of two types:

1) Controlled variables:

These are variables that can be controlled by management. By changing the input values of the controlled values, and observing the change in the output answers is the main activity of simulation. E.g. rearrange level and rearrange quantity.

2) Non-Controlled Variables:

These are the input variables that are not under management control. Usually these are probabilistic or stochastic variables. E.g. in pdn simulation the no. of breakdowns, in inventory-demand and lead-time.