ex-post forecast

[Former Member]

hi all

pls tell me the formula for the ex- post forecast for the

SEASONAL TREND FORECAST MODEL - 40 , 41

AND PLS TELL ME HOW TO CALCULATE

Edited by: raj on Jan 21, 2008 7:35 AM

[Former Member]

Hi Raj.

Sorry, Have now re-read your question.

Ex-post will be calculated using the initialisation and then

Trend/Seasonal Models w. 1st Order Exp. Smoothing.

The formula for this can be found (and the link to initialisation) at:

<erroneous link removed>

Correct link - http://help.sap.com/saphelp_scm50/helpdata/en/ac/216b83337b11d398290000e8a49608/content.htm

Hope this helps.

M

Edited by: percx on Jan 22, 2008 8:05 AM

Edited by: percx on Jan 22, 2008 8:10 AM

[Former Member]

Raj,

The ex-post forecast should be what the forecast would have been in that period based on the relevent forecast profile. For example, if the history from Jan through June is 50, 60, 70, 80, 90, and 100, respectively and you are using a 2 month rolling average forecast profile, the ex-post forecast for Jan through June should be 25 ((050)/2), 55 ((5060)/2)), 65 ((6070)/2)), 75 ((7080)/2)), 85 ((8090)/2)), 95 ((90100)/2)). The expost forecast values are used in determining forecast error.

Hope this helps.

Sean

[Former Member]

Raj,

The ex-post forecast will be calculated for you by the system. This is further used to calculate forecast accuracy. I am not sure what exactly are you looking for.

Rgds,

SB.

[Former Member]

hi

how to calculate the ex-post forecast manually

pls give the formula

[Former Member]

HI Raj.

There is no single formula. It depends upon the forecast model that you are using as to what formula it uses to calculate the ex-post.

In essence, the system tries to use the selected forecast model using the historical data to generate a forecast. i.e., if you selected linear regression it would use the linear regression calculation.

This is as Sean says.

Hope this helps.

M

Edited by: percx on Jan 21, 2008 5:37 PM

[Former Member]

hi

i expect the ex-post forecast for the seasonal trend forecast model

with regards

vbakyaraj

[Former Member]

Hi.

I apologise if I am not understanding your request, but I think this is exactly what you have been provided with.

Could you please elaborate on what you think is missing and I will try to help.

rgds, M

[Former Member]

Hi PERCX,

I expect the ex-post forecast formula to calculate the ex-post forecast for the seasonal trend forecast model

i cannot found in the help .

[Former Member]

Hi.

Sorry if it was not clear in earlier responses.

The ex-post is calculated using the formula for the selected forecast model. There is no

separate ex-post formula.

So, if you are using the seasonal trend model it will use the seasonal trend formula to calculate the ex-post

The only difference is for the initialisation where it calculates Basic Value, Trend and Seasonal parameters.

I have also noted that the link I provided fails take you to the correct page, try:

http://help.sap.com/saphelp_scm50/helpdata/en/ac/216b83337b11d398290000e8a49608/content.htm

This should get you there, the link to initialisation is there also.

Sorry for the "miss-link".

Hope this helps.

M