From XP to lean
By this point, if you are a frequent reader here you know that my thinking about agile development stems more from XP than SCRUM, though I have a pretty open interpretation of methods either way.I also have an undergraduate minor in production and operations management, so Rafael Tolotti’s post a couple of weeks ago about his experiences on a Lean Software Development project triggered me to look more deeply into it. I was especially interested in the notion of “deciding as late as possible”, #3 on Rafael’s list. So I followed his link (to Wikipedia, btw), which led me to other sites that had greater background. Without adding too much history to this post (which you can find out as easily as I did), Tom and Mary Poppendieck literally “wrote the book” on the subject, so I am going to accept and refer you to their site as authoritative for the purposes of this post. Anyway, the site speaks of this principle a little differently, as follows (currently under the heading “Learn Constantly”):
Last Responsible Moment
Learn as much as possible before making irreversible decisions. Don’t make decisions that will be expensive to change before their time – and don’t make them after their time!
[Incidentally, of the seven principles listed on Rafael’s Wikipedia reference, Poppendieck’s “Keep Getting Better” isn’t listed… it was apparently replaced by “deciding as late as possible”.]
It’s our responsibilityI have decided I like these distinctions, so of course I will adopt and adapt them in my use of life’s salad bar… while I continue to do some more research. One thing I really like is the use of the word “responsible” above. Responsibility requires that you accept being the cause of an outcome from the decisions that you make, for good or for bad. (Here I am not specifically speaking in a moral sense.) If you decide too soon, without enough information, you might guess right – you are more likely to guess wrong – but you are responsible nevertheless. If you decide too late… well, you are responsible for that, too. That, to me, is not the same as deciding “as late as possible”.
Still, it was Rafael that led me into this thinking. I am sincerely thankful to him for the gift of introducing me to new thinking, and I hope I do the same for you.So let me make some interpretations about how Rafael’s assertion provided significant and powerful meaning for me. As I think through all the projects I have worked on, there were some times we made decisions too late. Sometimes it appeared we made decisions at the right time. But I think most of the bad decisions came with too little information and we might done been better by just waiting for a season. I see two counter-arguments here:
- If pressure is to get to market quickly, we feel there is no time to decide… so we have to do it quickly
- If we have a concern for the foundation we build upon, we may want deeper insights and need to learn before deciding
But high throughput of business value is a key objective of agile development. So it makes sense that many agile projects lean toward #1 over #2 (no pun intended).Given the cultural predisposition on an agile team to keep plowing ahead, I can see how the original principle of Last Responsible Moment could become “Deciding as late as possible”… and I can see how the latter might resonate better with a pragmatic team of developers.
So, how do I resolve all of this? I am going to use both, but keep up the knowledge of the powerful underlying distinction from its source.As for you… do you see the different between “responsible” and “possible”? Put that way, maybe it seems more straightforward. What do you think could be the real impact of one principle or the other on the way a team thinks and the way it works together? How might the different philosophies show up in the code?