Which of the following is NOT a factor considered when evaluating User Stories for size?

When evaluating User Stories for size, the correct focus should be on factors that directly affect the effort required to complete the story. Effort, complexity, and level of doubt are all crucial components that help in estimating how much work a given User Story will require.

Effort refers to the actual amount of work that the team anticipates will be needed to implement the User Story, which is a key indicator of size. Complexity relates to how difficult it will be to fulfill the requirements of the User Story, influencing how much effort might be required. Level of doubt encompasses uncertainties or unknowns that could impact the team's understanding of the story and its implementation, which also factors into sizing because higher doubt can imply a potentially larger or more complicated project.

In contrast, duration is not typically considered when estimating the size of User Stories. Duration pertains to the actual time it will take to complete a task, which can vary based on a number of external and internal factors unrelated to the inherent size of the User Story. Therefore, it does not provide a direct measure of the User Story's size in terms of effort, complexity, or doubt, making it the factor that is not evaluated when sizing User Stories.