Story points...
Abstract Complexity, Not Time:
Story points measure the relative complexity of a task or user story rather than the absolute time it takes to complete. This abstraction allows teams to focus on the effort required to deliver a feature rather than getting bogged down in estimating hours or days, which can be highly variable and affected by external factors. Time is also heavily based on WHO is going to do the work. This can add another level of variable which can throw off the expectation for a sprint. If the individual who was “SUPPOSED” to work on the story is now no longer available, you MAY NOT have another individual as skilled to complete the work which risks a delay, or the work being deferred to another sprint.
Promote Relative Sizing:
Story points encourage teams to compare the complexity of one task to another, rather than estimating how long each task will take individually. This relative sizing helps in prioritization and planning, as it allows teams to quickly gauge the effort required for different tasks.
Reduce Pressure and Bias:
Estimating in hours or days can lead to pressure to meet those estimates, which can result in either rushing through tasks or padding estimates to accommodate potential delays. Story points remove this pressure and bias by focusing on the intrinsic complexity of the work rather than external constraints.
Accommodate Uncertainty:
Agile projects often deal with uncertainty and changing requirements. Story points allow teams to account for this uncertainty by providing a more flexible and resilient estimation mechanism. As the team gains more information about a task, they can adjust the story points accordingly without having to change time-based estimates & schedules.
Facilitate Team Collaboration:
Story point estimation is done collaboratively by the entire team, including developers, testers, and other stakeholders. This collaborative process fosters better understanding and buy-in from team members, leading to more accurate estimates and improved team cohesion.
Improve Velocity Tracking:
Story points are used to calculate velocity, which is the amount of work a team can complete in a sprint. Tracking velocity over time allows teams to predict future delivery dates more accurately and make data-driven decisions about scope and planning.
Allows you to focus on “points on the board” (think of sports here) over time:
Story points allow the team to “put as many points on the board” sprint to sprint. They are free of inherent time constraints which cause a team to potentially cut corners to meet a predetermined time commitment. This can lead to an infusion of tech debt and ultimately quality issues and delays. Focusing on points on the board and monitoring the outcomes for at least 3 sprints allows the team to establish a trend. This trend becomes the basis in which planning is rooted. The trend holds true IF the sprint duration is kept constant and the team is kept constant. If either changes the trend is null and void and a new trend must be established.
Point Consistency drives delivery consistency:
A team is incredibly consistent. Complexity evaluation and pointing from a group who have the same definition of a 1 pt story tends to yield relative point values of like kind work sprint over sprint. The team leverages the retrospective to understand where pointing was under or overestimated and continuously includes these experiences to calibrate how the team points. This results into an even greater stability of point consistency as well as a technique providing leadership the ability to plan with higher degree of probability & quality when features will be realistically delivered.