T-shirt sizing agile is an relative estimation technique. It is utilized to track and give a rough estimate to how much time or effort a epic / feature / task would be expected to take. It is my go to agile estimation tool when a product owner wants to quickly assess the size of their product backlog or when attending agile portfolio planning.
The opposite of t-shirt sizing would be an absolute agile estimation technique such as story points.
T-shirt sizing also helps make a determination of their agile teams ability, key stakeholders and dependencies. Using this information the product owner can clearly explain their priorities and team members can have a rough idea of who is responsible for a particular task and when they are responsible for it.
This agile estimation process is done by assigning each particular tasks with T-shirts sizes that can range from extra small to XXL. While t-shirt sizing estimation is mostly used by software development teams and engineers, it is an applicable tool for any type of team.
To help the teams align it to their day to day work, I put up a guide on how many sprints of work do they think the piece of work would take. This tactic works if your sprint is 2 weeks or 1 month they still have a relative time frame to complete the task.
When to do T Shirt Sizing
T-shirt sizing in Agile projects would be used during project kick-off to measure how much work is involved and if you have the appropriate people resourcing in the Agile team. This helps get management off your back as they are the ones who want estimates with endless backlogs even though its not the best thing for your product.
Estimates could be considered anti-agile or product management as it should matter how long it takes you should only be working on the most important thing to bring the most value to the product #NoEstimates
It can also utilized during agile portfolio planning to have a high level estimate of upcoming features a team can consider taking on without having to fully decompose to an absolute level such story point level. I do think relative estimates are good to help with capacity planning but should be taken with a grain of salt and not considered project schedules – that is the biggest mistake management make.
You should consider t-shirt size estimation when you need a quick estimate for the number of items and it allows for teams that are new to the agile estimation techniques a way to perform a better estimation method.
How to Do T-Shirt Sizing Planning Poker
To facilitate a planning poker t-shirt sizing session follow these steps:
- The agile product team are provided an overview of what each t-shirt size represents and provided the cards.
- The product team has been presented with the necessary information by the product owner. This could be done using a Agile charter or business case or simply an epic
- The team would select a playing card that represents their estimate and it is revealed to the estimators.
- If there are differences in the value each team member selects, they discuss their estimates and after discussion, reselects another estimate card.
- This process is repeated until there is a common goal on all of the values.
Agile development teams use planning poker in an agile project to estimate story points in a realistic fashion. Planning poker requires the consensus of the entire team and is structured in a way that the product owner would read an overview of a user story or describe a feature to those responsible in the development team for estimating the amount of work that is required.
Agile Epics & T-Shirt Sizing
Epics are parts that we want to have built into our product or process. They are large groupings that have the ability to be broken down into smaller user stories. Analyzing an Epic must include the Minimum Viable Product (MVP), which is considered the bare minimum requirement for a new product or feature.
While estimating Epics in the beginning stages can be difficult due to the limited amount of data, it is done through T-shirt sizing and is refined over time throughout the implementation of MVP.
Typically, Epics are done in a sprint time frame. The scrum team would initially meet for sprint planning to make a determination of which items should be handled in each sprint. Each T-shirt size correlates to the amount of sprints it takes to measure the completion of each Epic:
Sprints to Epic Estimating Chart
S – 1 Sprint
M – 2 to 4 Sprints
L – 5 to 6 Sprints
XL – 7 or more sprints.
Working in XL sizes are not ideal. If you have an Epic that is larger than 6 sprints, it would be important to break them down.
Agile Estimating Technique
T-Shirt Sizing Agile Example
When it comes to making a determination of an epic size when building a new website, it is important to center this build around your project team’s goals. Take for example that you would like to build a website that is designed for the supervisors of an organization to access and have functionality for documentation.
Epics are the big picture and each component of these would need to be broken down into user stories in order for them to have its full functionality. The Epics for developing the site would be divided into sprints and looks like this:
| Feature | T-Shirt Size |
| Register | Large |
| Login | Large |
| User Profile | Medium |
| Forgot Password | Small |
Benefits and Pitfalls
T-shirt sizing finds itself beneficial because it is a simplified way to have an estimate. Team members have the ability to spend less time thinking about a task or how much time it would take. Tracking t-shirt sizing in a planning session is designed to being a centralized tool so that everyone can see who is doing what and how much.
Subjectivity is common T-shirt sizing pitfall that occurs when implemented in agile development teams. There are times when clarity is needed in order to make distinctions between sizes as well as the ability to track an initiatives associated t-shirt size.
The main premise of the no estimates movement is that estimates do not directly add value to your process or work, so you should find ways to reduce the estimation process or even stop it if possible
Stop Estimating: The #NoEstimates Movement in Agile – DZone Agile
Tools for Creating T-Shirt Sizing Online
There are useful tools available that makes it easier for your team to create T-shirt sizing.
Two popular tools to utilize for creating T-Shirt sizing are Asana and Trello.
Asana: Has a method for t-shirt sizing for content projects. It is an assessable tool with a sharing function that allows for your workload to be managed for your team.
Trello: Utilizes custom fields that cater to assigning specific t-shirt sizes for projects. This program allows for you to make rules to have your cards organized in the order that you would like for it to be in. Trello also implements a sharing function that allows for your team have access.
Estimating Alternatives to T Shirt Sizing in Agile
A few alternatives to T-Shirt sizing in agile would be affinity mapping and planning poker. These two agile estimation processes carry a significant level of importance in the scrum process to best determine how much effort is required in development.
Fibonacci Series & Story Points
Story points represent the size, difficulty, and effort that is required for the implementation of a user story. The Fibonacci sequence is utilized as a scale to more accurately measure how much work goes into each sprint. The is a linear scale that is generated by adding two previous numbers together to produce the next value in the sequence. The sequence would be recorded like this: 0, 1, 1, 2, 3, 5, 8, 13, 21. Each story point estimate would then be assigned a number that is represented on the scale.
Affinity Mapping Product Features
Affinity refers to comparable backlog items related to ether types of code, varying areas of a product, or the type of effort required within product development. When it comes to affinity mapping within the agile estimation technique, each team will group items of similar size together.
What is affinity grouping in Agile?
To execute affinity mapping, the person facilitating the project would place the backlog items onto sticky notes and place them onto a wall. The team would then place them into the correct sizing category. After this is done, they will discuss each item to evaluate whether or not they are assigned appropriately. An important component of this process is that the team must move quickly and not overthink.
