The 85/15 Rule

There is a widely held belief that an organization would have few, if any, problems if only workers would do their jobs correctly. As Dr. Joseph M. Juran pointed out years ago, this belief is incorrect.

In fact, the potential to eliminate mistakes and errors lies mostly in improving the systems through which work is done, not in changing workers.

The observation has evolved into the rule of thumb that at least 85% of problems can only be corrected by changing systems (which are largely determined by management) and less than 15% are under a worker’s control—and the split may lean even more towards the system.

For example, a production line worker cannot do a top quality job when working with faulty tools or parts; a surgical nurse cannot do a good job with gloves that do not fit.

Even when it does appear that an individual is doing something wrong, often the trouble lies in how that worker was trained, which is a system problem.

Once people recognize that systems create the majority of problems, they will stop blaming individual workers. They will instead ask which system needs improvement, and will be more likely to seek out and find the true source of the problem.