Forecast model initialization query

[Former Member]

Hi,

I am using MRP type VM. Model : Trend, History period 7, Forecast period 4, Period indicator M, Initialization X and Selection procedure 2. Lot size is EX, Service level 80%, Planned delivery time is 75 days.

Consumption values are

07.2015	56
06.2015	91
05.2015	84
04.2015	98
03.2015	91
02.2015	47
01.2015	98

Alpha 0.2 and Beta 0.1 and using First Order exponential smoothing.

Ran the forecast for 01.08.2015 and the results are as below.

Basic value  70.674, MAD 18, Safety stock 31, Trend value -3, Error Total 36, ROP 196.

Forecast values for 8th month is 68, 9th 66, 10th 63 and 11th 60.

I have understood Forecast values, Safety stock and Reorder Point.

But, the basic value, trend, MAD calculations are not matching with whatever model initialization formula provides.

If historical period is 3, then it is working as per formula. If it is >3, then, there is some other factor coming into picture, I guess.

Searched so many threads/documents in this regard and unable to understand the logic.

Can you please guide me how the model initialization happens if historical period is >3. Please also let me know how the above trend/basic values are calculated.

Thanks and Regards,

Siva

[Former Member]

SAP note 22189 helped me resolve this issue myself.