Estimation & Sizing

Goal

Produce honest, useful size estimates for a backlog so the team can plan and prioritize — while making the deepest truth of estimation explicit: an estimate is a probability distribution, not a promise. A single number presented as a commitment is the root cause of most planning failure. This skill uses reference-class forecasting to anchor estimates in real outcomes, expresses results as ranges (P50/P90), and uses relative sizing to estimate fast. The output is a sized backlog where every item carries a confidence range, ties to ESTIMATION_TEMPLATE.md.