Pareto Principle and Software Development

In 1906, a study carried out by Italian economist, Vilfredo Pareto, found that the wealthiest twenty percent of the country’s population owned eighty percent of the land across his home nation. Pareto surmised that this pattern was reflected across the globe causing a form of social divide. It seems that it was Pareto himself who created the word, “Elite”, in order to describe his theory.

Romanian-born, American-raised, electrical engineer, Dr. Joseph Juran, evolved on this theory in 1941. He later admitted that it was erroneous on his part to give it the name, the Pareto Principle, as Pareto had confined his findings just to social and wealth issues. “’Pareto's principle of unequal distribution applied to the distribution of wealth and to the distribution of quality losses.’ Although the accompanying text makes clear that Pareto's contributions specialized in the study of wealth, the caption implies that he had generalized the principle of unequal distribution into a universal. This implication is erroneous. The Pareto principle as a universal was not original with Pareto.” (Juran, 1994)

Juran broadened the concept by applying it to wider society and, in particular, the business industry. “The vital few and the trivial many” was Juran’s take on what is also commonly called, the 80/20 rule. It is a simple observation that implies that eighty percent of output is the result of just twenty percent of the input. These observations have become more prominent in the field of business as companies attempt to capitalize on the findings. If, as appears, the majority of results come from such a relatively small group, it allows said companies to focus more time and resources into the areas in which they deem will produce the greater rewards financially and improve efficiency.

The Pareto Principle has been applied to a large number of industries over a long period of time. Dane Balia notes that software engineering, and software developers in particular, are “Still babes in the woods” when it comes to using the practice. (Balia, 2017) But as far back as 2002, Microsoft was just one organization that adhered to the 80/20 rule with then Chief Executive Officer, Steve Ballmer, stating;

It seems to be an easy logic to understand, with the positive attributes far outweighing the negative ones. To expand on Ballmer’s quote, if eighty percent of the errors are found in just twenty percent of the bugs, it is simple to presume that sixty-four percent of those errors are found in just four percent of the bugs. Then, finally, roughly fifty-one percent of the errors are found in just under one percent of the bugs.

This would suggest a high level of importance being attached to subscribing to the Pareto Principle in the computing and information technology industries in the ensuing years since. With so many variables existing in the results of a software development life cycle, it is vital to establish and maintain structural procedures that ensure efficiency, budget control, time management, good customer relations, quality assurance, etc.