Incomplete Product Backlog Items from a Cancelled Sprint
On page 9 of The Scrum Guide under the _Cancelling a Sprint_ section, it says when a Sprint is cancelled, all incomplete Product Backlog Items are re-estimated and put back on the Product Backlog. Then it goes on to say that "The work done on them depreciates quickly and must be frequently re-estimated."
Could someone please help me understand what this sentence means exactly, perhaps using an example? In what ways and why could the work done "depreciates" and what is meant by "re-estimation" here?
Thank you and have a nice day.
The Product Backlog is the list of features that might go into the product. Unless the product is perfect, there will always be something on this list. The only situation when a Product Backlog can be completely discarded is when the product is end of life.
The cancellation of a sprint is an exceptional event: the Product Backlog items under construction had the highest priority at the beginning of the sprint. Then during the sprint the priorities of the project have changed dramatically.
In the case a Sprint is cancelled there will be unfinished Sprint Backlog items. They have not met the Definition Of Done. So the state is unclear and they are not released.
When this work is put back on the Product Backlog, it should be re-estimated, so the Product Owner can compare the business value and remaining effort compared to other Product Backlog items.
When work is ‘half done’ and nobody is working on it, the knowledge about it will vanish. Hence depreciation. And depreciation should be (re)estimated, for it means losing value.
This is how I interpret the Scrum Guide. My own thoughts on a cancelled sprint would be to finish as much items to the Definition Of Done. Document the status remaining stuff that seems valuable. Scrap the rest.
> The work done on them depreciates quickly and must be frequently re-estimated.
This is referring to work that was in progress at the time of Sprint cancellation. An investment has been made in starting that work, but since it is not Done it cannot be delivered and the accumulated value cannot be released.
Undone work should be returned to the Product Backlog and re-estimated, but the investment made in Work In Progress still remains on-hand following cancellation. Since it is no longer being actioned, this work will lose relevance and can only depreciate in value. This will change the effort needed to complete any associated requirements...hence the need for frequent re-estimation as the value leaks away.
Thank you Christiaan and Ian for your explanations; things are much clearer for me now!