Agile Estimation Techniques: Story Points, T-short sizing and more

Agile estimation is the process of estimating the effort required to complete a story or task or feature in an agile project. Agile estimation techniques are used to help teams plan their sprints and ensure that they are able to deliver the project on time as planned.

The downside of estimating efforts beforehand is the inaccuracy involved. In Traditional projects, Resources and Time are estimated and requirements are fixed. It is more plan-driven. Where as in Agile project, resources, time are constant and features are estimated. This is more value-driven.

Agile (Value driven)Resources, TimeFeatures
Traditional (Plan driven)FeaturesResources, Time

Some of the commonly used agile estimation techniques are 

  1. Story point estimation
  2. T-shirt sizing
  3. Three-point estimate
  4. Affinity Grouping

While estimating the story or task or feature, the team has to consider the capacity available, team size, whether it is co-located, whether it has all tools and resources for the next sprint.

Story point estimation :

The story point is the unit of measure used to estimate the size of task or feature. The fibonacci series are commonly used (1, 2, 3, 5, 8,...) . 8 being the SAFe suggested number that projects 100% effort of a team member. The team can assign story points to a task or feature by many methods like “Planning poker” or “Show of hands” . Commonly used method for user story estimation.

T-shirt sizing

It is also a intangible unit of measure used to estimate the size of story or feature. This is commonly used for feature estimation to determine its overall complexity. The estimation is done as XS, S, M, L, XL. Feature estimation is important, so the Business team can rank and prioritize the roadmap backlog based of WSJF.

Three-point estimate

A three-point estimate is an estimation technique that uses three values to estimate the size of a task or feature: the most likely value, the optimistic value, and the pessimistic value. It can be a number. Used mostly in new teams, new projects where accurate estimation is challenging.

Affinity Grouping

This estimation approach works by having team members group similar items. If tasks seem related in scope and effort, you put them together until you have a clear set of groups. We can use the same set of values as other techniques (Fibonacci sequence), or make the groups more broad so it’s closer to the large, small, and uncertain method.

Leave your comment on techniques used in your teams.

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