Does individual work performance follow a Paretian distribution? O'Boyle and Aguinis (2012) wrote a paper arguing that individual job performance follows a Paretian distribution  rather than a normal distribution (put simply, a very long tail to the right, rather than a bell-shape).
The abstract was as follows:


  We revisit a long-held assumption in human resource management,
  organizational behavior, and industrial and organizational psychology
  that individual performance follows a Gaussian (normal) distribution.
  We conducted 5 studies involving 198 samples including 633,263 researchers, entertainers, politicians, and amateur and professional
  athletes. Results are remarkably consistent across industries, types
  of jobs, types of performance measures, and time frames and indicate
  that individual performance is not normally distributed—instead, it
  follows a Paretian (power law) distribution. Assuming normality of
  individual performance can lead to misspecified theories and
  misleading practices. Thus, our results have implications for all
  theories and applications that directly or indirectly address the
  performance of individual workers including performance measurement
  and management, utility analysis in preemployment testing and training
  and development, personnel selec- tion, leadership, and the prediction
  of performance, among others.


Question


Are they correct in claiming that most researchers assume that individual job performance is normally distributed?
Are they correct in claiming that the Paretian distribution provides a better fit to individual job performance than the normal distribution?


Reference


ERNEST O’BOYLE JR. HERMAN AGUINIS (2012). THE BEST AND THE REST: REVISITING THE NORM OF NORMALITY OF INDIVIDUAL PERFORMANCE. Personnel Psychology Volume 65, Issue 1, pages 79–119, Spring 2012 PUBLISHER SITE; also see UNIVERSITY PRESS RELEASE
An alert of a follow up paper ON THE DISTRIBUTION OF JOB PERFORMANCE: THE ROLE OF MEASUREMENT CHARACTERISTICS IN OBSERVED DEPARTURES FROM NORMALITY and subsequent search brought me to this discussion. I don't have full access to these articles unfortunately.

Of the two questions that posed, no, I wouldn't expect to find a normal distribution and no, I wouldn't expect to find a pareto distribution. As was mentioned in the G+ discussion that Artem linked to, what we tend to see is some skewed distribution such as a log-normal.

A good tool for exploring these types of situations, especially in a dynamic / systems-based situation is to use simulation.  This is what I did in a 2010 blog post on 'forced ranking' which at it's heart frequently assumes normally distributed performance.

The post shows selection of any sort quickly produces a skewed population. This selection can be either on entry level selection or during a performance review cycle.  What I didn't explore in that simple model, but again supports the outcome, is self-selection - i.e. the likelihood of an employee leaving is to some degree based on their assessment of fit.

I also explore what happens if we use a probability distribution not only for the individual, but also a distribution for the likely measurement error (because only in rare situations can be objectively measure performance.) For me this is the sort of instance where a Bayesian Hierarchical model makes sense.

In my day job working with senior HR people to help them understand their workforces I find simulation a powerful tool. We can make a few simple assumptions and show that over time unexpected results will occur.  Many times it will show that normal distributions don't logically hold over time.