INVESTing in User Stories, revisited

Mike Cohn’s “User Stories Applied” discusses using the INVEST mnemonic as a guide to writing better user stories. I was recently asked to dig up a reference for it, and found this presentation here, with the section on the mnemonic on pages 47 and 48.

As I read it, I noticed that there’s been a change to one of the letters. Whereas the book uses ‘S’ to denote ‘Small’, now it’s become ‘Sized appropriately’.

I think this is a change for the better, as I noticed that every time I talked someone through the acronym, I would have a long-winded conversation qualifying ‘Small’ as ‘Just small enough but no smaller’. This would come about as I tried to explain the tradeoffs between a story being small enough to estimate with some reasonable certainty, small enough to fit within an iteration, and still ensuring that stories are ‘V- Valuable to the customer’, needing to ensure that user stories continue to express clearly a problem or need of a person.

Overly small stories push us further from the original context of the problem, and thus force us to compensate with an increasing heirarchy of ‘super-stories’ to help us focus on the bigger picture. These become more noticable when working in shorter iterations than might be common on a Scrum project, so three cheers for Mike in spending the effort to come up with ‘Sized appropriately’.