In an excerpt from Agile Estimating and Planning by Mike Cohn, I came across an idea I hadn’t heard about before: using 0 to estimate really small items.
Although we haven’t started estimating the items in our still-in-creation Product Backlog yet, I am intending to try the Planning Poker technique using the Fibonnaci number sequence to estimate the size of each item. In the book, Mike Cohn suggests including 0 in the estimation scale. Sound crazy? It did when I first read it!
But read on … it does have benefits:
If all estimates must be within a certain range, assigning non-zero estimates to tiny features limits the size of the largest features.
If the work to do something really is that insignificant, assigning a 0 to it will avoid impacting the team’s velocity. Assigning a 1 may mean they need to undertake some more significant task to make the same velocity in a later sprint.
Assigning 0 could work as long as everybody on the team recognises that it’s a “free lunch” – and like free lunches, the number of 0 tasks in an iteration must be limited – it’s not an excuse to sneak in lots of extra tasks. 10 x 0 ≠ 0 in reality.
I plan to try this – but if it doesn’t work, I also like the alternative of grouping a number of tiny tasks into a something big enough to represent a 1. Either way, it will be interesting to see how the team accept it.