Market definition can be achieved via a Sales, Epi, Opportunity or Patient Flow based forecast
Sales based forecasts are effective for short-term tactical forecasting for "stable markets".
Epi Patient Based
Epidemiology based forecasts start with a population and by applying a series of filters estimates the size of target patients.
Splits treated patients into stable vs opportunity groups (e.g. new, switch).
Patient Flow Based
Follows a cohort of patients over time and captures progression to different disease states.
Two main ways to trend historical data - based on its characteristics, data availability and/or user's knowledge
Judgemental based trending
User defines trend by inputting key assumptions such as expected end share and type of uptake curve.
Algorithm based trending
The trend automatically calculates, based on historical data using pre-set algorithms selected by the user.