​​Institute for Healthcare Improvement
Boston, Massachusetts, USA​

The key to solving a problem is to first truly understand it. Often, our focus shifts too quickly from the problem to the solution, and we try to solve a problem before comprehending its root cause. What we think is the cause, however, is sometimes just another symptom.

One way to identify the root cause of a problem is to ask “Why?” five times. When a problem presents itself, ask “Why did this happen?” Then, don’t stop at the answer to this first question. Ask “Why?” again and again until you reach the root cause.

This technique is attributed to Taiichi Ohno, father of the Toyota Production System, which revolutionized automobile manufacturing with methods now known as Lean.