The Role Of Story Points: Measuring Relative Effort Rather Than Absolute Complexity

Defining Story Points

Story points are a unit of measure used by agile software development teams to estimate the overall effort required to fully implement a user story. They provide a relative estimate of difficulty rather than an absolute measure of time. Some key attributes of story points include:

Allow teams to gauge effort and difficulty of user stories in relation to each other
Based on the overall effort required to deliver a user story
Requires discussions between cross-functional team members during estimation process
Scalable across large agile teams with varying skillsets and capacities

What are story points?

Story points assign a numerical figure to each user story that signifies the relative level of effort and complexity involved. They enable agile teams to estimate how much work can be completed in a sprint based on the team’s historical velocity – the amount of story points the team can handle per sprint.

Some defining attributes of story points:

Table of Contents

Relational measure rather than specific amount of time
Gauge both complexity and effort of work rather than just duration
Require cross-functional input across product, design, engineering during estimation
Represent overall effort to complete user story, not just development tasks

Story points vs time estimates

Story points differ from time estimates because they do not directly correspond to hours or days. Instead, they relatively quantify the expected effort and difficulty. Time estimates assume predictable speed of task completion while story points acknowledge many variables that cause uncertainty and flux.

Some key differences between story points and hours:

Story points communicate level of effort whereas hours represent duration
Hours can imply false precision. The further out the estimate, the less reliable hours become
Factors like code complexity, testing needs, and experience levels influence how many hours a task will require
Story points relative scale accounts for unknowns better than estimating hours

Relativity of story points

The magic of story points lies in their relativity. Rather than precise measurements, they create room for the inherent variability of knowledge work. Some elements that story points successfully accommodate relative to hours estimates:

Team capacity and velocity over time based on growth and learning
New complexities emerge during implementation otherwise unknowable upfront
Individual strengths and weaknesses evolving across team members
Technical challenges can vastly swing time needed irrespective of size

Using Story Points Effectively

Leveraged successfully, story points fuel collaborative estimation and sprint planning while supporting capacity adjustments over time. Some best practices include:

Frame user stories for relative comparison during estimation sessions
Calibrate point scale based on team makeup and type of work
Observe patterns over past sprints to guide forecasting
Inspect velocity trends to identify process improvements

Sizing user stories

When writing user stories to size, best to frame needs statement to facilitate relative comparison. Rather than prescribe solutions upfront, focus on what the user requires.

Strong user story examples:

As a user, I need to update my password so I can enhance my account security
As a user, I want to recover my credentials so I can access my account if I forget my login details

During estimations, team will gauge story difficulty by comparing to other stories they have completed.

Planning sprints and releases

With relative story points, teams can plan sprints by summing points for each sprint based on previous velocity. Patterns emerge after 3-5 sprints to guide forecasting.

Likewise at release level, summing story points for features provides user value roadmap to help plan milestones for larger initiatives. Epic story points help determine release scope and timeline combinations.

Tracking progress

For executing sprints, daily standups help identify obstacles so team can still hit sprint commitment. Burndown charts visualize if work completed matches story points to date.

If burndown line trends higher than baseline, there are impediments. If it trends lower, more story points assigned than bandwidth. This transparency helps calibrate story points to team capacity over time.

Common Misconceptions Around Story Points

Due to their relativity, story points can be misunderstood by teams new to agile methodologies. Common areas of misinterpretations include:

No 1:1 correlation between story points and development hours
Varying team velocity as skills grow
Effort orientation rather than complexity only

Story points do not equal hours

Teams can wrongly treat story points as synonym for hours. But direct conversion defies the fluid, relative nature of story points. With complexity, unknowns, and learning curves, hours cannot neatly map.

Rather than hours conversion, story points represent work effort in an agile environment adaptive to change. Fixed hours assumptions risk misleading forecasting.

Story point velocity varies

Velocity defines how much work in story points a team can handle per sprint. Unlike hours estimates, velocity will vary sprint to sprint for agile teams as skills expand.

For example, early velocity ranges around 25 story points per sprint. After a year, same team could double to 50+ story points per sprint as their capabilities grow.

Velocity informs how many story points to allocate per sprint. It emerges from team output rather than prescribed upfront. In turn, this guides story point forecasting across releases.

Effort, not complexity

Story points represent overall effort that includes many factors – not just technical complexity. Effort encompasses elements like coordination needs, uncertainty levels, setup costs, user validation, security considerations etc.

While complex code can require significant effort, simpler workflows can have deceptively high effort if spanning multiple systems, touch points, and processes with downstream impacts.

Story Points in Action

To better understand applying story points, let’s walk through an example user story to size, incorporate into sprint planning, and map progress during the corresponding sprint.

Exemplary user story

Consider the following user story:

As a user, I want to connect my social profiles so I can import my contacts from social networks to more easily connect with friends already on the app.

Point scale for above story

During estimation, product and engineering size this story as 5 story points after comparing relative effort to recent stories, such as:

Update password workflow = 3 points
Retrieve forgotten username = 1 point
Change account email = 2 points

The social import requires more effort compared to above since it interfaces with external systems, introduces new connections infrastructure, handles edge cases etc. So it is pegged at 5 points on team’s scale.

Sprint planning with story points

Historically, the team has averaged 20 story points per sprint. So for this sprint, they aggregate top stories totaling 20 points including social import story.

Product owner includes social story given stakeholder requests and user needs. Engineering feels they have bandwidth for integration based on velocity.

Daily standups track progress on stories. Burndown chart marks if story point burn matches baseline for sprint commitment.

Summary

When properly leveraged, story points power agile teams to scale efforts, accelerate learnings, and calibrate capacities over time. The key merits include:

Relativity – Size user stories based on comparative effort rather than prescribed time estimates
Team Calibration – Velocity metrics and burndown rates help teams gauge sustainable pace and improve processes
Adaptability – Story points flex with new learnings discovered mid-sprint, allowing work adjustment

For those new to story points, the most critical guidelines to remember are:

Avoid tying story points to specific hours per point
Let velocity emerge from team output over first few sprints
Use burndown indicators to inspect impediments and process chokepoints
Re-baseline story points for team makeup changes or new project types

With these principles, story points can greatly serve agile teams striving for rapid value delivery through adaptive, ever-improving systems. Exploring their full potential takes some calibration, but pays dividends over time through more accurate forecasting, increased team autonomy, and ultimately better product outcomes.