Reducing MRP Forecast Requirements

Forecast requirement values created during the forecast run are displayed on the time axis as issues:

• When calculating the current stock/requirements situation (displayed in the stock/requirements list), the system reduces the current period's forecast requirements by the consumption figures from the same period which have already been posted.

• The same procedure is also used for calculating material requirements, that is, the system successively consumes forecast requirements with withdrawal postings.

In MRP, the reduction of forecast requirements only differs in two aspects:

• the results of the forecast are available for planning as forecast requirements for unplanned consumption.

• forecast requirements are reduced by unplanned consumption from the same period which has already been posted.

The results of the forecast are transferred to material requirements planning as forecast requirements and are displayed on the time axis. In the following example, the reduction of forecast requirement quantities is shown by consumption.

Reduction of forecast requirement quantities

	Forecast reqmt	Available for plng	Withdr. posting	Reduction	After reduction
Period 1	1000	1000	400	400	600
Period 2	1000	1000	0	0	1000
Period 1	1000	1000	1200	1000	0
Period 2	1000	1000	0	200	800

Goods issue results in a withdrawal posting and reduces the current period's forecast requirement by the amount withdrawn. If the goods issue was higher than the corresponding forecast requirement, the remaining amount is subtracted from the following period's forecast requirement.

In this example, a goods issue of 400 pieces was posted in the first period. As a result, the forecast requirement of 1000 pieces was reduced by 400 pieces. In the first period, 600 pieces are still available for planning.

If consumption (that is, the goods issue) (1200) in the first period is higher than the original forecast requirement (1000) then the forecast requirement for the following period (1000) is reduced by the remaining amount (1200 - 1000 = 200). That means that in the first period, 0 pieces are still available for planning and in the second period, 800 pieces.