concept boomerang in category software development
This is an excerpt from Manning's book Specification by Example: How Successful Teams Deliver the Right Software.
Another good metric to check if you’re doing something wrong is checking for the presence of boomerangs. A boomerang is a story or a product backlog item that comes back into the process less than a month after it was released. The team thought it was done, but it needs rework. But it’s not a boomerang when the business later extends existing requirements to incorporate innovation as the product evolves.
Once you implement Specification by Example, the number of boomerangs should be reduced significantly until they’re a rare occurrence. Collaboration on specifications and better alignment of testing and development should eliminate wasteful rework caused by misunderstanding. Reviewing your boomerang trends over several months will show you how much you’ve improved. If the rate doesn’t drop, it means that there’s something wrong with the way you implemented the process.
Tracking boomerangs doesn’t take a lot of time, usually a few minutes every iteration, but it can help a lot when the time comes to challenge or prove that Specification by Example is working. In larger companies, it can also provide compelling evidence that it’s worth doing with other teams. For more complex statistics, you can also track the time spent on boomerangs, because this figure directly translates into wasted development/testing time and money. If people complain about the time spent on automating executable specifications as unnecessary overhead, compare that to the time they spent working on boomerangs several months earlier. This should be more than enough to build a business case for Specification by Example.
Once the number of boomerangs goes down and they occur relatively rarely, you can stop tracking them. If a boomerang occurs, try to understand where it’s coming from. One of my clients had many boomerangs coming from their financial department. This pointed to a communication problem with that particular part of the company; as a result, they looked for better ways to engage the department.