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Projected stock vs Carry over negative projected inventory.

Hi experts,

We are using the supply heuristic at our project in week mode. Moreover, we have set the CARRY_OVER_NEGATIVE_PROJECTEDINVENTORY parameter of the SCM operator to 'YES', so our negative stocks are transferred to the Net demand of the next period. We now see the following results:

So we see that the negative projected stock -41 is taken into account in the Net Demand of the next period (41 - (-41) = 81, due to roundings). This triggers a transportation receipt of 85. The result is a projected stock at the end of the second period of 44. This is because of standard setup of the Projected Stock, which is calculated as

PS(t) = MAX { PS(t-1); 0 } + Receipts(t) – Supply(t)


So basically, the negative projected stock is taken into account in our net demand, but not in the projected stock, which gives an incorrect view. Now it seems that 44 is the projected stock at the end of the period, but this is not the case, as is also clear when you look at period 3 (dependent demand of 1029 results in net demand of 1026, difference being the quantity of 3 which is the real projected stock (85 - 41 - 41)).

If we would remove the CARRY_OVER_NEGATIVE_PROJECTEDINVENTORY parameter, the result would be:

This is more correct from a projected stock point of view, but now we have not taken our negative stock into account. This would result in lost sales, which is worse than late delivery. Also not the ideal situation.

Is there any way to get to the following result (which would be a correct and realistic result):

You see that this is a combination of the first and second situation. Here, the Net demand is the dependent demand of the second period + the negative stock that was carried over. Both are covered by the transportation receipts. This results in a 'leftover' or projected stock of 85 - 81 = 4. This is than used in the next periods.

Is there any way to achieve this?

Best regards


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1 Answer

  • Best Answer
    Jan 19, 2018 at 12:48 PM

    Hello Kristof,

    Please provide screenshots with same planning view, but with 3 additional Key Figures: INVENTORYTARGET, TOTALRECEIPTS and SUPPLY.

    Best regards,

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    • Hello Nikolaos,

      The issue was not reproducible at the end, so we couldn't identify the root cause.

      If you are facing a similar issue, please also create an incident under component SCM-IBP-SUP-ALG requesting to assign it to me and mention this thread in the incident.

      Best regards,