Re: forecasting

A simple exponentially smoothed average on the figures you present does in fact 
give a decreasing average over the last four periods.

My own experience with the BPCS Forecasting module was that much of the 
statistical coding was actually in error - calculations in the wrong sequence 
and coding in the programs that was not completed (abandoned) - the result was 
that forecast numbers were produced but they clearly had not truly adhered to 
the statistical method they were meant to be emulating. This was only corrected 
by extensive re-programming of the statistical calculations by the SSA client 
concerned. I personally (whilst working for SSA) attempted to have the 
corrections made but it was never high on anyone's priority in Chicago and I 
would believe that no corrections have since been made to the erroneous coding. 
The only standard method that did not need correcting was the method that uses 
the previous years actuals as a forecast.

Note that the incorrect use of seasonality - when there is no statistical 
seasonality present in the data can have unpredictable effects on your forecast 
results and trends.

Regards,

Stewart

  ----- Original Message ----- 
  From: MisterBPCS@xxxxxxx 
  To: bpcs-l@xxxxxxxxxxxx 
  Sent: Tuesday, April 13, 2004 2:11 PM
  Subject: forecasting


  Hey gang,
  I have a client trying to use forecasting and the computations look 
  reasonable but when looking at the trend (which should be going down) are 
going up. The 
  illustrations are:

  Period     Start Date     End Date       Demand     
    12        12/01/03      12/31/03          71.00   
    11        11/01/03      11/30/03         208.00   
    10        10/01/03      10/31/03          58.00   
     9         9/01/03       9/30/03         303.00   
     8         8/01/03       8/31/03          73.00   
     7         7/01/03       7/31/03         162.00   
     6         6/01/03       6/30/03         394.00   
     5         5/01/03       5/31/03          96.00   
     4         4/01/03       4/30/03         471.00   
     3         3/01/03       3/31/03         192.00   
     2         2/01/03       2/28/03         188.00   
     1         1/01/03       1/31/03         264.00   
    12        12/01/02      12/31/02

  And




  Any one have any suggestions as to why the issue?
  Thanks,
  Ric Weide
  rcweide@xxxxxxx
  or
  MisterBPCS@xxxxxxx



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