Improving Value Streams

Value streams are the flow of work from start to realized value. The Lean mantra "flow when you can, pull when you must" sums up how you'd like work to take place in a value stream. Anything that slows down the work (hand offs, handbacks, waiting for someone) is not a good thing. This is why Lean suggests looking at delays in workflow and feedback. These delays typically cause waste.

Delays in workflow usually appear as:

1. A handback in a value stream
2. The need for someone’s help who is not available – either because they are in another value stream or because people within a particular value stream are not coordinating well

Value streams can be improved by:

1. Keeping work within the capacity of the people in the value stream
2. Allocating people to a value stream so that are available as needed – note, when not possible, use a kanban system to manage the work to be done by these people
3. Attend to the workflow in a value stream so that people don’t need to wait for each other (e.g., have cross-functional teams)
4. Have a workflow where handbacks aren’t required (e.g., test-first)

Value streams also provide a way to see how work in one part of it effects work in other parts.

Note: SAFe has redefined value streams to some extent.

In lean, the term "value stream" means "the set of actions that take place to add value to a customer from the initial request through realization of value by the customer. The value stream begins with the initial concept, moves through various stages for one or more development teams (where Agile methods begin), and on through final delivery and support."

You don't define them, they represent what is. You can, of course, define what you'd like them to be and to take actions to improve them. It's important to refer to value streams as "what is" and "ideal" or "what we want" value streams as something we want to create. Then we can see what steps we need to take to improve our value streams. 

One last point. In an article on value streams, SAFe claimed:

"By their very nature, value streams are long-lived and generally independent of each other"

This is not correct.  The major cause of multi-tasking is that value streams overlap with each other (not independent). And project thinking has them be short-lived.