MS Level 1 Part - Consumed Forecast

  • 15 September 2020
  • 1 reply


On a MS level 1 part IFS seems to be adding in numbers to the consumed forecast column that is then effecting the projected balance of the part and we don’t understand why? The forecast is entered manually into “demand forecast” page therefore previous the week is over written we believe so there shouldn’t be any figures in this column.

Is this to do with the promise method? (set to Available to Promise).

Forecast Consumption currently set to “drop”.



1 reply

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First, before I forgot to ask, which version do you run? It looks like Apps9 to me.

The unconsumed forecast is calculated like this:

Actual demand is consuming from the forecast columns ( 0 and 1). So in your case the demand on the 23rd is trying to find forecast on that date or an earlier date to consume from. But there are no forecast to consume in your example. System continues with the demand on 28th, still no available forecast to consume. … Moving forward… in the 15th October there is a demand of 4 which finds unconsumed forecast the 5th October. The unconsumed forecast is initially 8 but becomes 4 during this operation. 

Forecast Consumption happens prior to calculation of Master Schedule Receipts and calculation of Projected Onhand.

Projected Onhand is basically calculated like this: Prevoius Projected Onhand - Demand - Unconsumed Forecast + Open Shop Order supply => temporary result. And if this temporary result goes negative, the level 1 calculation triggers a Master Schedule Recipt (sometimes called MPS receipt or just MPS or Master Production Schedule), so that Projected Onhand goes to 0 or the safety stock level.

You can change the consumption logic by allowing forward forecast consumption as well. Then system first tries to consume backwars, if there is remaining demand to consume, logic looks at forecasts after the actual demand date.

You can get some understanding of how forecast consumption works by looking at the action messages you have in the tab Action Messages. 


The way we calculate Unconsumed Forecast has nothing to do with the Promise Method.

I hope this helps you to some extent. Hard to explain everything about MS in this forum.

Good with your planning!