Our team breaks down user stories in sub-tasks, then estimate their sizes in hours using the planning poker technique. The numbers we use are 2, 4, 6, 8, 12, 16, 24, 32 and it goes just like story points estimation using the Fibonacci sequence.
Are there techniques/games exclusive to hours estimation?
There are many "games" (strategies) to make estimation, One that I like is:
This was shown by the authors of Managing the Unmanageable when we requested a work-shop from them to improve our processes. I think they might have further suggestions in their website ;).
Beside planning poker, 1 of the other estimation techniques we used in our team is 3-Point estimation technique, which is well known in project management world, specially while estimating the activities.
Like Planning poker game, this 3 point estimation can be done like below
we can invite the project development team into room
product owner explains the user stories and sub-tasks or activities to be done to complete the user stories.
each team member provide his/her 3-point estimate (Optimistic, Most likely and Pessimistic) for each sub-task
After team agreed on what is right Optimistic, Most likely and Pessimistic estimations are, triangular distribution formula can be used for activity/sub-task estimation as follows,
tE = (tO + tM + tP)/3, where tO = Optimistic , tM = Most likely , tP = Pessimistic estimate, on which team had a consensus.
This is bit harder than planning poker, but also gave us more accurate estimates too.
We found it useful to use when not much historical data is available for similar user stories.
