This is the simplest model available and assumes that the underlying trend for the item has been rising (or falling) by approximately a constant amount per month during the period of history selected.
- IFP will obtain a trend line of overall best fit to the adjusted historical data
- This trend line is then projected into the future
- Note that for this model all selected historical periods are given equal weight
- Forecast values are then obtained by multiplying by the average seasonal factor for each month
An example trend graph is shown below.