I'm a big fan of value streams. I like the idea of being able to map out the process from concept to cash. Intuitively it appeals to my sense of order. I can see every step in the process and assess the process time and waste involved with each. I could track the whole thing with a stopwatch. How very, very Fredrick William Taylor of me... Yes, I fell right into that trap. It's easy to do with value streams. The problem starts with the metaphor itself: a stream. Streams are very simple. They run one direction, usually downhill. They typically have relatively few branches or tributaries. A stream implies a simple linear progression from start to finish. But that's not how value is delivered. Instead, organizations are networks, not streams. They are complex aggregations of people. And for better or for worse, work doesn't get done along simple linear paths. This is especially true for knowledge work. In fact, in knowledge work, we often don't even know the starting point for the process, let alone how it will work its way through the system. Networks are dynamic and changing. That's what makes them awesome and it's also what makes them hard to portray as a value stream. They aren't linear, they change quickly, and they don't have well defined start and end points.
Another problem with value streams is that they are typically uni-dimensional: they only track one thing at a time (usually some unit of work per time). Organizations however, have multiple dimensions to them. There is the flow of work, flow of money, flow of information, flow of emotion (around the watercolor), flows of traffic, and the list goes on. Using value streams to simply identify the work is like peering through a keyhole at the world - you are only going to see a very limited picture of the world. So while I still love the idea of a predictive world with well defined starts, steps, and end points, I'm afraid that's a bit of a Tayloristic fantasy. The reality is much more complex. It's a network, and traditional value stream mapping is pretty much useless for representing networks.