Estimation in sprint

Are you talking about the estimation of work on the Product Backlog or the Sprint Backlog?

Ian Mitchall,

I am talking about the estimation on both Product Backlog Items and Sprint Backlog.

Thanks.

What does the Scrum Guide have to say about "the act of adding detail, estimates, and order to items in the Product Backlog", and what sort of process that act is?

What does the Guide have to say about "estimated effort" in the Sprint Backlog and the event in which such work is planned? What does it say about when "estimated remaining work is updated"?

Ian,

As per scrum guide, adding details, estimates and ordering of items is done mainly in backlog refinement or backlog grooming meeting.

And estimated effort is updated as work is performed or completed in a sprint.

But I need clarification on estimates during backlog grooming and the estimates done during sprint planning?

If a backlog item is estimated in grooming meeting, should it be estimated again in sprint planning meeting  ( how part) ?

I think estimation at backlog grooming level is very high level , although details are added in user story/backlog item but it is not divided at task level. A PBI is divided at task level in planning meeting and then possibly good/accurate estimates can be done.

So an estimated PBI at refiment/grooming meeting will be re-estimated in planning meeting ( after adding tasks to it ) ?

Thanks....

Is there any reason not to keep estimates up to date, where they are thought to be inaccurate, so the best possible forecast of work can made at the necessary time?

Even though the team may estimate an item prior to Sprint Planning, the option should always be available for the team to revisit an estimate and change it if more information is learned or made available that can affect the size of the item.  

A PBI's estimate should be available for modification all the way until the item is offered and forecast during Sprint Planning.

We estimate the user stories in story points during backlog refinement meetings.. and do revisit those once more during the Sprint planning to make sure it's still correct based on current understanding and if it requires changes, we update it based on inputs from the team members. The task level estimation are in hours and not in story points and is done during 2nd part of the Sprint planning and not during backlog refinement meetings.

Ian," Is there any reason not to keep estimates up to date ", yes there is no reason not to keep estimations up to date. But estimation at planning meeting is not optional I think. We have to do task level estimations in how part of sprint planning meeting as explained by Debashis Mishra. So can we conclude that a PBI must me estimated in detail ( task level) in sprint planning ( how part ) and we cannot rely on the estimation done in grooming meeting.

Azhar, I will acknowledge that I find little if any value in task estimation, but your last statement sticks out to me:

we cannot rely on the estimation done in grooming meeting

What reason(s) might you have to conclude that previous PBI relative estimation is unreliable?   Keep in mind that from a Lean perspective, we should not be doing anything that does not provide value (waste).

So can we conclude that a PBI must me estimated in detail ( task level) in sprint planning ( how part ) and we cannot rely on the estimation done in grooming meeting.

No. What you have described is only one possible implementation, even though it is certainly a very common one. However, a team might reasonably choose to do no further estimation at all when they address the second topic of Sprint Planning.

For example, the Guide says that work is decomposed "often to units of one day or less". That process of decomposition into the said units may be sufficient, during the Sprint, for the team to understand how much work remains on their Sprint Backlog at any given time.

Remember that Scrum does not mandate the formulation of tasks, still less task-level estimation. The important thing is that the team forecasts a selection of PBI's for meeting an agreed Sprint Goal, and has a plan for achieving it which can keep track of how much work is thought to be left.

The totality of that forecast of work must be achievable. Understanding the totality may require no more estimation than that of the associated Product Backlog Items during Product Backlog refinement.

Timothy Baffa, my statement " we cannot rely on the estimation done in grooming meeting " was in fact a question. I needed answer to this and Ian explained it very well.

Thanks Ian for your kind explanation.