How to Use T-shirt Size Estimation in Jira

Estimating work in agile project management is important – and about as enjoyable as shoving a paper clip in your eye. Trying to judge how long a task is going to take and how complex it’s going to be is a giant guessing game that agile teams try desperately to simplify.

The estimation methods available in Jira are all numerical. The most commonly used is story points. Number-based estimation has its problems, which is why lots of Jira users are crying out for something else.

May I present Jira T-shirt sizes.

What is T-shirt size estimation?

T-shirt sizing is a quick and dirty agile estimation method that’s simpler and easier to use than story points.

Basically, you assign a T-shirt size – extra small (XS), small (S), medium (M), large (L), extra large (XL), or extra extra large (XXL) – to a task or user story based on the effort required to complete it. It’s a way of doing away with number-based agile estimation (although some teams assign numerical values to the different T-shirt sizes – we think that’s kinda against the point).

T-shirt sizes versus story points

“I am not sure I invented story points but if I did I’m sorry now.😇"
- Ron Jeffries

There are two main problems with story points.

The first is that story points make people mentally equate points to hours/days. If you tell a newbie who asks how you estimate, “a point is about a day’s work”, then you’re missing the, er, point. Agile estimation should be about size, not time. It also means you’re assuming the team’s velocity, i.e. how many points you can do in a day. But velocity is something teams discover by measuring it as an average over time.

The second is that story points are more exact than they need to be and can lead to debates over whether a Jira ticket is worth 2 points versus 3 points or 5 points versus 8. Discussions that waste time and make estimation harder.

T-shirt sizing solves both these problems.

You’re more likely to estimate the size rather than the duration of the work. You wouldn’t naturally think of a T-shirt size in terms of hours or days, like you might end up doing with story points.
There won’t be any nitpicking over specific estimates. A conversation about an S versus an M is more worthwhile than one about whether the work is 2 points or 3. The whole process is easier, too, just like it’s easier to go into a store and pick a medium T-shirt than try to work out if you need a 38, a 40, or a 42.

How do you forecast with T-shirt sizes in Jira?

One of the reasons teams resort to story points is that if they’re not counting points, how can they measure velocity? And how can they forecast the next milestone based on it?

Simple. Count the number of Jira issues you complete in a sprint instead. Because velocity is meant to be an average over a period of time, completed issues is nearly always as accurate a measurement of velocity as completed story points.

T-shirt sizing in Jira pros and cons

Let’s take a look at the overall advantages and disadvantages that come with Jira T-shirt size estimation, so you can work out if it’s the right approach for your team.

Pros

Estimation becomes a visual process if you’re imagining T-shirts rather than numbers, which makes estimating easier.
T-shirt size estimates can be agreed quickly, which is good particularly if you have a substantial number of items.
It’s easier to think “size” rather than “time” with T-shirt sizing, as it implies a range rather than an absolute number.
T-shirt sizing helps Jira newbies perform better estimations.
You won’t start assuming your team’s velocity.

Cons

T-shirt sizes are not a standard field in Jira; you’d need to create a custom field for it, and a custom field would only allow you to select a letter, e.g. XL. Therefore you lose the benefit of T-shirt size estimation being visual.
It can be more difficult to get all team members thinking the same way about what different T-shirt sizes mean, leading to inconsistent estimation.
Some teams will want to convert T-shirt sizes to numerical values in order to calculate velocity (although we’d argue that they shouldn’t; count issues instead).
Even if teams use T-shirt sizes to eliminate numbers from their estimations, someone somewhere will start equating sizes to numbers, e.g. S = 10, M = 20.

How does T-shirt sizing work?

Like most things agile, there’s no one-size-fits-all.

All teams first need to decide how many T-shirt sizes they’re going to have. Then, when it comes to actually estimating each task, you should aim for a consensus among the team.

How you do this is up to you. One method is silent voting, where the story or task is described, then each team member privately chooses a T-shirt size based on how complex they think the issue is, and how much effort will be required to complete it. Participants should consider the issue relative to an established baseline or previously estimated issues.

Afterwards, if there are discrepancies among the team, they can discuss it with a view to aligning their understanding.

Can you do T-shirt sizing in Jira?

As T-shirt sizes aren’t one of the standard Jira field types, you’d need to create a custom field. You could then have a dropdown and select S, M, L, XL, etc. on each issue. So, yes, there’s no reason why you can’t do T-shirt size estimation in Jira.

However, one of the advantages of T-shirt sizing is the visual aspect. By just having a letter, e.g. M, appear on your Jira issue, you lose that. Increasingly Jira users are seeking ways of making their tickets more visually appealing, something Atlassian sadly haven’t given much thought to.

So if you do want something more visual, and more representative of the actual thought process between T-shirt sizes, then you’ll need the Jira app Awesome Custom Fields. Awesome Custom Fields allows you to display a graphic of an actual T-shirt in your Jira issue.

You can also choose a color and display size for each of the shirts.

The Jira T-shirt size field that comes with Awesome Custom Fields makes the estimation process more intuitive. The visual aspect makes it less likely that team members will start to equate numbers or times with the size of a Jira issue. It also enables them to glance at an issue and know instantly what size it is, because pictures speak louder than words!

Importantly, Awesome Custom Fields offers an extension for Jira Service Management (JSM) users. This makes most of the fields, including T-shirt sizes, available for IT and other service teams working in JSM. Service teams may want to use T-shirt sizing to estimate change requests such as the implementation of a new process or system.

Awesome Custom Fields comes with a range of other agile estimation fields if your team wants additional options. These include a price tag field for estimating cost, and a Weighted Shortest Job First (WSJF) field for estimating and prioritizing based on size and value.

To summarize (aka TL;DR)

If you want to estimate more quickly, easily, and visually, and do it with fewer complications down the line, choose T-shirt sizing over story points.

You can do T-shirt size estimation in standard Jira, but you’d need to create a custom field that lets you select a letter (XS, S, M, etc).

If you want a field that’s more visual and intuitive, Awesome Custom Fields offers a Jira T-shirt size field that displays a customizable graphic.

If you’re looking to enhance your Jira project management and add visual aids to your tickets, book a personal demo of Awesome Custom Fields, or you can download the app for free on the Atlassian Marketplace.

Get Awesome Custom Fields for Jira Software

Get Awesome Custom Fields for Jira Service Management