I’ve picked up Kane Mar’s habit of playing rock, paper, scissors to estimate Product Backlog Items. This is a great way to get everyone’s estimate at the same time and provoke discussions between the outliers that wouldn’t happen otherwise. We go 1-5 for stories small enough to do in one Sprint, then 10, 50, 100, etc. for “epics” that need to be broken down into stories. The point is to communicate the numbers are rough guesses, not something to agonize over.
Another popular technique is to play “planning poker” using Fibonacci numbers. If a team is already using these I wouldn’t change it, but I don’t teach teams to start doing this. To do it right, everyone has to have cards with all the numbers on them, and show their cards at the same time. But estimation meetings can happen anywhere, any time you have the whole team together. The added bother of having to use the cards, plus the effort of explaining the Fibonacci sequence, plus the false impression there’s something magic about these numbers doesn’t seem worth it to me. My second choice (after rock, paper, scissors 1-5) would be powers of 2 I think. Most engineers have those memorized already, and it clearly communicates that the estimates are rough orders of magnitude.
Mike Cohn writes that a lot of teams prefer the Fibonacci sequence.
If you do choose to use Fibonacci numbers I still recommend playing “planning poker” to get a cross section of opinions at the same time. I’ve attached a PDF with some cards of a modified Fibonacci sequence you can print on heavy stock and cut out.
Another technique we’re finding pretty useful is T-shirt sizes with
corresponding powers of two. Registered users can download these here:
http://danube.com/system/files/T_Shirt_estimation_cards.pdf. Nonregistered users can
download these from the ScrumDevelopment Yahoo Group.
The Kinkos near my place was able to print these on card stock and
round the corners so they felt like regular playing cards. When we
get a round ‘tuit (besides the wooden one Jim Shore gave me) we’ll
get these printed onto real cards as Mike Cohn suggested and probably
give away some decks.
Danube Technologies, Inc.