On Measuring Performance and the Bell Curve

I have recently had an interesting conversation with one of our surgeons about clinical performance and how to improve on it. The talk inevitably led to a discussion on the validity of the bell curve, and how surgical performance can be improved once you are in the top performing zone. As you probably know, the bell curve has been used for years as a model on how people perform. As the image below shows, this model is easy to understand and stipulates that human performance fits a normal distribution, with most performers being average and occupying in the middle, while poor performers and high performance as outliers. 

However, in 2012, a research study involving over 600K participants
challenges the accuracy of this normal distribution model. It actually proves that 94% of these groups did not follow a normal distribution, but rather a "power law" distribution, whereas a small number of "superstars" generated the most performance (see image below).

What this means is that the normal distribution assumption (figure 1) is a myth when it comes to employee performance; 80% of employees actually below average, with the top 20% performance at the high end of the red curve, and another 20% of employee under-performing (bottom of the slope). 

To quote Josh Bersin:

“The really big difference between the “bell curve” and the “power curve” is that the power curve reflects the fact that a small number of people deliver an inordinate amount of contribution. This means that "most people" are below the mean. It does NOT imply that most people are lower performers, only the fact that the variability of performance is high and that the curve should not be equal above and below the mean.”

And back to our initial question: how can you improve your performance once you are at the top of the slope? Well, you actually can't. Unless you look at ways to improve the performance of your team, the people who fall below the 20% of the high-performers. This will mean higher level strategy initiatives like perhaps re-organizing and re-designing programs so that compensation is increased based on the value that people bring, step away from the "fairness" of the bell curve and create opportunities for people to perform at their highest potential...? 

As a surgeon, your intention to increase your performance by motivating your team to perform better might be a challenging task. In organizations where the bell curve is still the model for measuring performance (and IF these performance measurements really happen), with unionized workers compensated on contracts based on seniority rather than value delivered and a rather varied team composition (think 'versatility' of nurses rather than 'specialized by service') the challenge is on.