Forecast

Intent: Predict completion time based on the estimated size of a backlog and a known velocity

Proverbs:

• • If we are to understand the future we must look at the past

  • Forewarned is forearmed

Motivation: Agile teams must be prepared to respond to change, and cannot always make a delivery commitment. Yet even in conditions of extreme uncertainty, it is valuable to have a provisional timeline based on existing data and clear assumptions.

Structure: A team has an ordered backlog of items to deliver. The team only allows a limited number of items to be work in progress at any one time. The velocity or throughput can be calculated by inspection and a forecast made regarding the likely time of delivery for items remaining in the backlog. Metrics are captured iteratively on a timeboxed basis. The method used to derive these metrics and make such forecasts can be adapted by the team in order to improve their usefulness.

Applicability: Forecasting is used in most agile methods in order to determine the likely deliverables by the end of a given timebox.

Consequences: Forecasts can be mistaken for commitments and it is important to qualify expectations accordingly. The accuracy and value of forecasts diminishes the further into the future they extend.