Gunnar Ahlberg - Into software home

T-shirt estimate

Published 2012-01-23 - Stockholm

How do you estimate the size of something unknown? Here’s a working example from my client.

We estimate relative to other things. We call this “T-shirt estimates” and is something agile practitioners have used for ages. When the project leads meet for estimation, we set aside two hours for estimation. The actual discussion centers mainly around what is to be implemented in order to give the user real value. We spend most of the time discussing the feature. After that, we say “1-2-3” and simultanously call out “small” or “medium” or “large”. That’s all. If there is any disagreement, we continue our discussion until we agree.


That’s all! No time is spent on waste like “he / she could do this in an hour” - sure they can. But that’s is not relevant. What is relevant is “to satisfy the customer through early and continuous delivery of valuable software” (from the agile manifesto) and we want to know when the custorm

So lets se