Root Cause - time for a metaphor reflection


Recently, root cause analysis (RCA) has been he subject to review and critique.

I think we would be better served if we approached our analysis with more consistency to the metaphor. A root is a system — often fibrous, tangled and more dispersed than we imagine. It's also underground and when difficult to ever know when it ends. Furthermore, a root system very often will relies on microbial symbiosis — a dynamic process not discoverable with cursory examination.

The five whys are commonly used in QI analysis. Why why why why why is more likely to depict the root like a carrot — where the thinking and analysis repeatedly drills down into the same (few) lines of inquiry. Very often this thinking exercise is not substantiated with data or objective analysis. The opinions of a few command the greatest attention and become the subject of change intended to make improvement.

The fishbone diagram is causal theory in which participants of construction are directed through a categorical consideration of potential causes that create an undesired effect. This notion of finding “root” causes pervades both training on this method and its application.

What if there is no root cause? What if the system is complex and efforts to isolate a cause for amelioration is fundamentally wrong? How can you know when the "diagnostic" is complete? Sometimes (often?) we will need to test theory with PDSA because no amount of analysis will give us THE root.

See: The problem with root cause analysis
BMJ Q and S (open)