This is the fourth post about Dan Vacanti’s book Actionable Agile Metrics for Predictability, An Introduction and how it relates to *TameFlow*. The most interesting points found in chapter 3 were:

- You really need to understand Little’s Law and when it is applicable.
- In order to get work done faster, you need to work on less stuff.
- Little’s Law is exact between any two time points when WIP is zero.
- Little’s Law can be applied exactly between the start and end points of a Minimum Marketable Release (MMR).
- In a
*continuous flow* process, care must be taken to guarantee *conservation of flow* and to keep the process in a *stable state*.
- One can consider the assumptions of Little’s Law as process policies
- When process policies warrant the assumptions of Little’s Law, the entire process becomes more predictable.
- Process policies ultimately determine the performance of your process.
- Use Little’s Law and the underlying assumptions as guidance as to how to design and govern your process.
- Even with segmentation and categorizations of work in progress (WIP), Little’s Law still applies, both for the segments as well as for the aggregate of WIP.
- Work items do NOT have to be of the same size in order for Little’s Law to apply.
- Little’s Law describes the past, and it should not be used to predict the future.
- Predictability is more about having a system that performs according to expectation, rather than making exact forecasts.

Now we will look at what Dan has to teach with regards to *Cumulative Flow Diagrams*, which he describes in chapters 4, 5 and 6.