A couple of weeks ago I wrote about the basics of evaluating a trauma system and last week I posted about over &  under triage.  This week is about a tool we use to measure whether we’re striking the right balance- the “Z Statistic”.

Back in 1990, there was a famous study published (Major Trauma Outcomes Study) that reviewed thousands and thousands of trauma patient records to develop a statistical formula to benchmark the risk of dying from blunt (crushing or fractures) or penetrating injuries (gun shots, or cuts).  That formula has been updated and today serves as the basis for the Z Statistic evaluation that we use to look at how many folks are/are not surviving based on their particular set of injuries.  We look at our survival rates compared to that statistical formula and we provide that information to each of the level I trauma centers so that they can look at their results against the (blinded) aggregate information for the other hospitals. 

When we wrote our trauma rules a number of years back we did a good job of making sure that the trauma hospitals had to have performance improvement teams in place including what are called morbidity and mortality reviews to look at key cases that can serve as an opportunity for learning and improving care.  Next week I’ll share the results for these Tools (Over & Under Triage, Z Statistic) plus a few others that we’re regularly tracking and provide an overview of how we use the data to move our system forward.