Completion of a task is accomplished by performing a sequence of steps.  The more steps in the sequence the more likely you are to make a mistake; either by forgetting a step or doing the step out of order.  One method for reducing the likelihood of making a mistake is the creation of sub-tasks.  This is where the analogy to dancing comes in to play.

When you first learn to dance you learn basic steps; the waltz’s box step, the tangos 8-count “Slow, Slow, Quick Quick Slow”… Once the basic step is mastered (and heaven help me one day I will master the box step) then additional “sub-tasks” can be learned.  There are four virtues of sub-steps.

1. Low chance of order mistakes:  shorter tasks have a lower risk for errors due to their simplicity
2. Low cost for errors: if a mistake is made in a sub-task it is, often, isolated to that sub-task and it can be quickly re-run
3. Decomposition: frequently when broken into sub-tasks, the task can be distributed to multiple people.
4. Ability to chain together: The sub-tasks can be decomposed into multiple “routines” and reused in multiple processes.

In general, processes that have 3 ~ 5 steps are considered “easy” to remember and master.  Going above 8 steps in a process results in increased possibilities of human error.