T-Shirt Sizing

T-Shirt Sizing is an agile estimation method that uses T-shirt sizes (XS to XL) to assess the complexity or effort required for epics or features. This approach simplifies communication between technical and non-technical teams and fosters a shared understanding of priorities and necessary resources.

Walkthrough

1. 1

   Introduction to T-Shirt Sizing

   10 min

   The facilitator explains the concept of T-Shirt Sizing, specifying that each T-shirt size represents an estimate of the effort or complexity of a task. They might say: 'Imagine that each task is a T-shirt, ranging from XS for the simplest to XL for the most complex.' Participants are invited to ask questions to clarify the concept.

   Tip — Use concrete examples of past tasks to illustrate each T-shirt size.

2. 2

   Preparation of Items to Estimate

   15 min

   The facilitator asks participants to list the epics or features to be estimated on post-its. They clarify: 'Write each item on a separate post-it.' This allows for easy visualisation of the items to be estimated and enables movement during discussions.

   Tip — Ensure that each item is well understood by all participants before moving on to estimation.

3. 3

   Group Estimation

   30 min

   Participants discuss together to assign a T-shirt size to each item. The facilitator facilitates the discussion by asking questions such as: 'What similar tasks have we completed before?' or 'What are the risks or unknowns associated with this item?'.

   Tip — Encourage each member to express their views to prevent certain voices from dominating the discussion.

4. 4

   Consensus and Adjustment

   15 min

   Once the initial estimates are made, the facilitator helps the group reach a consensus. They might say: 'Does everyone agree with this estimate? If not, let's discuss the differences.' Participants adjust the sizes if necessary.

   Tip — Use facilitation techniques like 'Fist to Five' to quickly gauge the group's level of agreement.

5. 5

   Summary and Prioritisation

   10 min

   The facilitator summarises the estimates and discusses with the team the prioritisation of items. They might ask: 'Which items need to be addressed as a priority?' This helps align the team's efforts with strategic objectives.

   Tip — Use a chart to visualise the items in order of priority, which will facilitate future planning.

Variants

• Use different coloured post-its for each T-shirt size to quickly visualise the estimates.
• Incorporate an anonymous vote for each estimate to reduce the influence of opinion leaders.
• Add an 'XXL' size for exceptionally complex or uncertain items.