Below is a graph of durations in the scheduling and process of just the in-room surgical parts of a typical OR case.  Most of the items can be altered by policy and by the conscious effort of the people involved in doing the tasks. There are lots of connections and some necessary events—hence the title of this blog:”butterflies and nails”.  A few items that can be altered have a profound effect on the flow of the case and OR schedule for the day (time and money) like the butterfly that beats it’s wings in China and causes a hurricane in the Bahamas.  And some items, like ‘for lack of a nail for the shoe of the horse–which lost the battle–which lost the war’, can be critical.  A good model can help find the nails and the butterflies that are important (concepts, models, and simulation).  Of course, a bad model is like a bad GPS….over the cliff and through the woods.

One take home point is that there are many factors influencing the outcomes of a process.  Anyone who gives you a couple of statistical numbers or accounting calculations and says something is impossible, not feasible, a money loser, or great— without giving you a model that explains and jives with the reality you know—should be suspect of being mad, and possibly dangerous.