Scenario: Let's say there are two items A and B in the product backlog of a Scrum team. From a PO point of view B has more customer value than A and is therefore ranked higher. When asking a developer for the estimated time to work on these items he gives the following input:
- A takes 2 days
- B takes 2 days; but if A is done before then B only takes 1 day (as some prerequisite work is done in A as well)
This means that, when B is done first and then A, the overall time for those two work items is 4 days. But when A is done before B the overall work time will be 1 day. But this will be against the priorities as B is ranked higher than A.
Please assume that both work items cannot be completed in the same sprint. Otherwise, there is no need for this question :)
Actual question: Should estimates incorporate such information?
Our thinking: We've been discussing this yesterday on whether the estimates for work items should keep this in mind. Should a PO have this information to reorder the product backlog based on this information? We came to the conclusion that estimates should not contain this information, i.e. B takes 2 days time, period.
The reasons for that are:
- The product backlog is ordered based on customer value
- When B shares a task with A, what about the other items? There will probably be more tasks like that that need to be looked at. This will lead to long lasting discussions without a reliable result.
Are we missing sth. or is our thinking correct? There are probably more reasons to add to that list.