Seasonality
Seasonality is considered in the conversion for the annual frequency to monthly frequency.
Seasonality is implemented by a means of "normalized to 12" in the Simulator as followed:
To illustrate how seasonality affects the conversion of annual frequency, let’s assume that the user inputs a Poisson “annual frequency” with lambda= 4800, and by applying trend, exposure, etc, other factors, we already have "monthly frequency" with lambda= 400. T he seasonality vector is <2,1,1,2,1,1,2,1,1,2,1,1>.
The entire discussion above carries through for the negative binomial distribution also. For this distribution, the “size” parameter would be treated in a manner analogous to lambda for the Poisson distribution.