How am I suppose to estimate these stories if the specs aren't clear yet

Last post 03:28 am March 3, 2014
by Ludwig Harsch
7 replies
Author
Messages
01:32 am February 28, 2014

Hi all,

I'm sure you all have ever ran into the following situation/scenario during estimation at the sprint planning/ refinement session.

"How am I (we) suppose to estimate these stories if the specs aren't clear yet? It can change anytime so it's useless to estimate now!"

What do you (the scrum master) usually say to this?

07:58 am March 1, 2014

Nothing can be 100% clear before dev.
If you want 100% accuracy, go back to waterfall and its analysis / design / dev phases ;-)

08:33 am March 1, 2014

Posted By Olivier Ledru on 01 Mar 2014 07:58 AM
Nothing can be 100% clear before dev.
If you want 100% accuracy, go back to waterfall and its analysis / design / dev phases ;-)

If you are working in a company where the developers are used to the waterfall way of working, saying things like "go back to waterfall" isn't really gonna help...

08:36 am March 1, 2014

Posted By Olivier Ledru on 01 Mar 2014 07:58 AM
Nothing can be 100% clear before dev.

Oh in that case, I'll throw a 100 because it's not clear enough and I know more problems will arise along the road...

(playing the devil's advocate now, I hear this a lot from developers)

04:30 pm March 2, 2014

In agile there is the tendency to separate size from duration in estimates. We estimate size and then measure duration.

To be able to do relative estimation you could try to do the following:

- Get acceptance criteria for the stories
- Determine a couple of story attributes you ca use for estimation. For example UI complexity, algorithm complexity, number of external interfaces, testing difficulty, etc
- Choose two reference stories that you use for estimation

Good luck,
Cesario

07:17 pm March 2, 2014

Posted By Cesario Ramos on 02 Mar 2014 04:30 PM
In agile there is the tendency to separate size from duration in estimates. We estimate size and then measure duration.

When you coach/train a scrum team how do you explain the definition of size?

I used to ask the team to come up with complexity but there were many discussions about low complexity/high effort and high complexity/low effort. Nowadays my definition I has asked been effort/complexity/uncertainties.

03:01 am March 3, 2014

The Scrum Master's job is to coach the Product Owner how to write the stories and to coach the team how to estimate them.
It is correct that the spec will usually not be complete and may change, because analysis is part of the sprint.
However there are parts of the spec which influence the size of a story and should be clear before estimating, and other parts can be decided during the sprint.
If you are not sure which part is missing, ask the team: Can you estimate without knowing this detail? They will tell you.

03:28 am March 3, 2014

If they cannot estimate, the Scrum Master should facilitate communication between PO and Dev Team in order to understand the story better and add details. The PO might accept drawbacks to keep the complexity low.