Relative estimation is a cornerstone of Agile measurement that shifts teams away from predicting exact hours to comparing work items against each other. Instead of asking "How long will this take?", teams ask "Is this story larger, smaller, or about the same as that one?" This approach acknowledges the inherent uncertainty in knowledge work while still providing the structure needed for planning. When teams estimate relatively, they bypass the false precision trap that often leads to missed deadlines and eroded trust. A task that one team member thinks will take 3 hours might take another 8 hours based on experience and skill level. Relative sizing cuts through these differences by establishing a shared understanding of complexity and effort.

Story points serve as the common currency in relative estimation, representing a combination of complexity, effort, and uncertainty. Unlike hours, points don't expire with the workday. They represent the overall size of the work regardless of who tackles it or when they start. The beauty of relative estimation lies in its speed and alignment benefits. Teams can rapidly size dozens of backlog items in a single session, creating a shared mental model of what constitutes "small," "medium," or "large" work in their unique context.^[1]