In practice, I alway run into teams that likes big stories. If they have big stories, there work is more efficient and that will give better result … so they think. But in real life what you see is that bigger user stories:
- Are harder to estimate correctly
- Are easy to under estimate
- Are being tested to late
- Are harder to keep focus on the necessary acceptance criteria
- Etc, etc.
Also when you put only one or two big user stories in a sprint, the chance that you will fail to finish the half or whole sprint is substantial.
So what to do? Split up those big user stories! Make sure you will have a few smaller stories in your sprint instead of one or two big ones. Actually, i think you can apply the 7 plus or minus 2 rule here; put a minimum of 5 user stories in the sprint. I have seen it happen: 3 user stories of 3 point have been finished faster than 1 user story of 8 points, for real! Another advantage is that you will get much faster feedback from you customers, which you can use to improve the whole.
So how do I split up these user stories? Well, there are some predefined patterns for splitting up the user stories. These are described in the following blog posts:
Thats it for now, hope this gives you inspiration to pick up more and smaller stories in your sprint and see it work! Any feedback is welcome.