Driver quantity is the number of units calculated by the driver formula. The calculation is based on whether the behavior-table row that is accessed by an assignment rule contains a unit value or a total value.
When a behavior-table row contains a unit value, the driver formula calculates the number of units that are involved in each transaction that is picked out by the selection criteria. The number of units appears in the Driver quantity field. Then, the cost for that transaction (Value) is determined by multiplying the number of units (driver quantity) by the unit cost (in the behavior table) of the transaction.
When a behavior-table row contains a total value, the driver formula calculates the number of units that are involved in each transaction that is picked out by the selection criteria. Then, the cost per transaction is determined in the following way:
- The total number of units for all transactions (picked out by the selection criteria) is calculated by adding the number of units (as determined by the driver formula) for each transaction (picked out by the selection criteria). The number of units for each transaction appears in the Driver quantity field.
- The cost-per-unit is calculated by dividing the total value (in the behavior-table row) by the total number of units.
- The cost for each transaction (Value) is calculated by multiplying the cost-per-unit by the number of units (as determined by the driver formula) for that transaction.