Sooner Safer Happier: Antipatterns and Patterns for Business Agility

by Jonathan Smart

Lead time distribution, as per Figure 8.9, is a useful visualization. It shows the number of days from when the work started on an item of value until it is in the hands of a customer (x-axis) versus the number of times that that same lead time occurred (y-axis). The curve typically shows a Weibull distribution, which is like a normal distribution skewed to the left. There is usually a long tail of long lead times. In this histogram view, it’s recommended to measure the 85th percentile. This means that with empirical evidence, any similarly sized item of value (ideally all are roughly the same size, small), there is an 85% probability that it will be done within that amount of time. Plot this chart regularly to see how its shape is changing. When the 85th percentile point moves to the leftover time, then you are delivering value Sooner to customers. (See Figure 8.9.)

Useful metric