It’s been some time from the previous chapter of the Kanban Story but it doesn’t mean we’ve stalled. There’s an interesting concept which I keep referring to but only recently realized I’d never really written about it.
The concept is called standard-sized features.
If you read about Kanban you just have to be familiar with the term Minimal Marketable Feature, which is a piece of functionality which is as small as possible, yet sellable to a potential customer. It is a very nice concept and that was exactly what we started with when we were adopting Kanban.
However, after some time we realized that we sacrificed marketability of our features in order to get them similar in size. This change wasn’t really planned. It just seemed more convenient on occasions to split the work that way.
It might be easier for us since we were never orthodox with MMFs. After all how could you possibly marked some architectural changes or rewriting one of integration interfaces from scratch? Anyway that wasn’t a reason to come up with standard-sized features (should I call them SSFs?)
SSFs were born because we needed to prepare some estimates for fixed price projects even though for most of these projects preparing estimates was the only activity we were performing. It is a kind of situation when you don’t really want to invest lots of time yet you still want to come up with some reasonable numbers in case you actually get the project and are expected to deliver it.
In such environment MMFs can be tricky. I can perfectly market a feature which consists like a couple dozen lines of code if it is the right code in the right place. On the other hand for some other features you may need tons of code until finally there is something which can possibly be sold to anyone, assuming that they’re partially crazy and would buy some half-baked functionality.
So yes, MMF can differ vastly in size. And this renders your average measures, like average cycle time, pretty much useless. If variation of cycle time is big so you may deliver it in 2 days but you can also deliver it in 2 months, depending on what kind of MMF it is, you can’t base on average or median. This way if you’re out of luck and get a bunch of huge MMFs you’re also totally screwed.
The answer can be SSF. With standard-sized features you don’t really care what you can market. Actually that’s probably not the case for majority of teams since we rarely directly sell our crap… I mean products. SSFs however allow you to deal neatly with estimation. You can use some simple methods to come up with a number which would go into a formal agreement like instantly, no matter how hard you try to explain a salesman what coarse-grained estimate really means.
Another nice trait of SSF is it helps make flow smoother. If feature’s size differs much you tend to have those big tasks hanging there for a longer time. It makes the team less flexible, as part of the team is dedicated to work on this specific task, and it consumes part of the limit for a longer time which may yield some blockers.
One of arguments against SSFs I heard is it’s pretty hard to learn how to get features standard-sized. Probably if you want to make them all delivered in 9 days sharp it is hard indeed. However you don’t aim for such accuracy. Variation between 6 and 12 days is completely enough. Anyway the surprising thing, at least for me, was we quickly became pretty good in splitting the work into standard-sized chunks of work. It looked like we didn’t even try and got it right, so we just kept doing the good job.
Standard-sized features proved to be valuable so you might consider them as one of options when deciding what exactly you want to have on your sticky notes you put on the Kanban board.
If you liked this story make sure you check the whole Kanban Story series.