Number of Periods per Seasonal Cycle
Dear DP Statistics Experts,
I have a very basic question
Scenario:
I have 4 years of historical demand calendar month wise
For a given Product (which is my selection ID on which forecast is being executed)
Every March-April and Oct-Nov each year, I have higher than average demand
Every Jun-July each year I have a lower than average demand
I know this highs and lows are because of certain events of rejoice and gloom resp and not really outliers.
I now create a forecast profile with a seasonal time series model. For reasoning sakes les use seasonal linear regression model 35
I use last 48 months of History and I generate forecast for next 24 months.
We are now in June 2013.
There is a parameter in the univariate profile > Model Parameters called PERIODS that expects a value of Number of Periods per Seasonal Cycle.
Given the above information what value should I enter here
A) 2
B) 4
B) 16
C) 12
D) 36
E) Some other Value
F) Ask the Client.. well he doesn't care or know either
G) Don't bother: Test each of these, get ok from the client and bill the client for the time taken
Assume that I am executing my statistical forecast in monthly periodicity with past periods = 48 and future periods = 24 on Product as a selection criteria.
I am not using Seasonal Planning in DP.. I don't know what is in there. This is standard APO DP.
The F1 help says this. Owing to my poor English language skills, I am unable to understand what this means esp. the one in bold below
Number of Periods per Seasonal Cycle
Specifies the number of periods (for example, months) in a season.
Procedure
If you are using a seasonal model (forecast strategies 30, 31, 35 and 54) or
a seasonal trend model (forecast strategies 40 and 41), or if the system is to
carry out a seasonal test (forecast strategies 52, 53 and 55), enter the number
of periods that make up a season.
Dependencies
The period is specified by the planning buckets profile you enter in the
master forecast profile.
Thanks
BORAT