Monday, March 19, 2007

The Predictability Paradox

We had just several months earlier started our implementation of Scrum to all of our project teams. As we were learning what to do, more importantly we were learning things not to do. One of the things I found challenging in our adoption of Agile was that many felt that the traditional (Waterfall) way we were delivering software before was more predictable and that Scrum would be totally unpredictable given its emphasis on focusing one iteration to the next instead of heavy upfront requirements, design and planning. I knew in my heart that Waterfall really couldn't predict any better but really couldn't put my finger on why. It was then that I read this paper called "Lean Development and the Predictability Paradox" that I got my answer. It was this paper that changed my thinking and introduced the Lean concepts to apply to what I had already learned with Scrum. Here is the introduction (read more including more details on each aspect of Lean by downloading the paper here):

Wall Street has little sympathy for companies that can’t meet their forecasts every quarter. In turn, senior management expects department managers to make and meet forecasts. By the time these expectations arrive at an IT department, meeting forecasts often becomes a significant challenge. Unfortunately, it seems that a large fraction of software projects fail to deliver on their promises for one reason or another.

Why is it that software development projects seems to have so much difficulty delivering predictable outcomes? It seems that all too often projects are late or over budget or they deliver the wrong system or all of the above. How can the predictability of software development outcomes be increased? This executive report discusses a dilemma: in our zeal to improve the reliability of software development, we have institutionalized practices that decrease, rather than increase, the predictability of outcomes.

The best way to achieve predictable software development outcomes is to start early, learn constantly, commit late, and deliver fast. This may seem to cut against the grain of conventional project management practice, which is supposed to give more managed, predictable results. But predictability is a funny thing; you cannot build with confidence on a shifting foundation. The problem with conventional approaches is that they assume the foundation is firm; they have little tolerance for change.

The paradox is that trying too hard to create predictability creates opposite effect. Conventional practices are fragile in the face of change, and even in the face of learning. And yet, the more complex the system, the more necessary learning becomes. What is needed is an approach that encourages learning, and does not commit until learning is complete.

It should be obvious that decreasing the amount of speculation involved in making a decision increases predictability of the outcome. If you can make decisions based on facts rather than forecasts, you get results that are more predictable. Lean development is the art and discipline of basing commitments on facts rather than forecasts. It starts earlier, encourages change, freezes decisions later, and delivers faster than traditional practices, but nevertheless lean development produces outcomes that are more predictable.

The paradox of lean development is that you have give up some of the trappings of predictability in order to get true predictability. You have to abandon some conventional wisdom to gain the benefits of making decisions with more certainty. Fundamentally, you have to develop the capability to respond to events as they unfold, rather than hold dear the capability to orchestrate events in advance.

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