Which estimation technique is primarily used for estimating effort in Agile software development?

In Agile software development, planning poker is the primary estimation technique used for estimating effort. This technique fosters collaboration and encourages team participation in the estimation process. In planning poker, team members use a deck of cards with values representing the effort required to complete a user story or task. Each team member independently selects a card, and once everyone has made their selection, the cards are revealed simultaneously. This approach helps to bring out different perspectives and insights, leading to discussions about the complexity and effort involved in the work. The outcome is a more informed and consensus-driven estimate.

The other techniques mentioned, while they have their valid purposes, do not suit Agile estimation as effectively. Story mapping is primarily a visual exercise used for understanding the product and its user stories, rather than directly estimating effort. Function point analysis focuses on measuring the functionality delivered and is more applicable to traditional software development methods. Use case estimation can also provide insightful information but is typically more structured and less collaborative than the estimation provided through planning poker, which aligns better with Agile principles of teamwork and iterative progress.