Working backwards from a possible future state to determine how it might unfold.

Whereas Forecasting is the process of predicting the future based on current trend analysis, Backcasting approaches the challenge of discussing the future from the opposite direction. Typically, several alternative scenarios are examined -- usually representing different normative (or desireable) states. The question is then asked, if we want to arrive at Scenario A, what trends would need to change to get us there.