As real-world events and trends highlight the limits of our predictions, there is a growing recognition of the value of explicitly considering uncertainty in travel forecasting. This webinar considers contrasting approaches to considering that uncertainty. The prospective approach, presented by Mr. Daniel Engelberg, considers what may go wrong in travel forecasts and how those potential errors would affect the outcome. The retrospective approach, presented by Mr. Hoque, considers what has gone wrong in past forecasts and how actual outcomes compare to those forecasts. The output of both approaches is a range of forecasts that capture the expected uncertainty. Following the presentations, Dr. Rachel Copperman and Ms. Tara Weidner will lead a discussion of the trade-offs and potential complementarity of these approaches.