If your team is not experienced in estimating in story points — try estimating in T-shirt sizes! =)

Working in agile team I found at the beginning it is quite difficult for some people to switch from estimating in man-days to estimating in story points. The main complexity is to understand two things:

  1. story points express the size, not duration;
  2. and the size is relative, not absolute.

If you notice, your team-mates say "story points", but they mean/discuss/refer to man-days/man-hours — it is time to give a try the T-shirt sizes. The technique is to abstract the numbers and instead use the terms like Small, Medium, Large, eXtra Large. As you can see the T-shirt sizes better correspond to estimation in relative size.

After such estimation session you can convert the sizes back to numbers and send to the business. Hope it helps.

Comments

Sameer Navare wrote 6/12/2012 at 4:17 PM Hi
I have one query.  If we start estimating in just sizes leaving numbers behind, how will we come to know what is the capacity of our team?
I mean, if my team velocity is 250 hours then in this "T-Shirt Size Estimation" technique, how will I come to know, how much work should I take for my current sprint?
My team should not get overloaded and at the same time there shuld not be idle hours.

Please help

Regards
Yauhen wrote 6/13/2012 at 11:23 PM Hi Sameer,
As I wrote in the blog post, at the end of estimation session you should convert the sizes back to numbers. I suggest to use Fibonacci numbers. It is up to you which number to assign to which size. Then you should pick up as much work as you fill possible to implement in one Sprint. At the end of the sprint you calculate your velocity and continue the process. After 2-3 sprints you will know your velocity better and you will be able to take correct amount of work. Does it help?