The Constant is replaced by a Base value, and an additional Multiplier parameter, representing an annual growth (or decay), commonly used to specify tariffs.
Base
The value of the time series in a certain year, usually year zero, as specified by the Base Period below.
Multiplier
An amount which multiplies the previous year’s value in each year. A value of 1.05 represents 5% annual growth, while a value of 0.95 represents a 5% decline. The Multiplier parameter must be positive, and no greater than 2.
Base Period
Specifies a particular period when the Base value should apply. This can be a year, a quarter, a month, or even a fully-qualified date.
The value in year n, Tn, is calculated as:
Tn
= b ·
mn–c
where
b = Base input
m = Multiplier input
c = Base Period or zero.