What Root Cause Analysis Can and Cannot Prove

Root cause analysis, or RCA, is a method developed in patient safety to understand why an adverse event happened. It looks past the immediate error to the conditions that allowed it: the active failures at the sharp end and the latent conditions built into the system. Done well, RCA is rigorous and illuminating. Used carelessly in litigation, it can be stretched to say more than it should. Understanding both its power and its limits is essential to using it honestly.

Start with what RCA can do.

It can map how an event unfolded, identifying the sequence of actions and conditions that led to harm. It can distinguish active failures, the errors of the people directly involved, from latent conditions, the design and organizational weaknesses that made those errors more likely. It can apply established frameworks, including human factors analysis and the study of how defenses fail in sequence, to explain why safeguards did not catch the problem. And it can assess preventability, asking whether reasonable system changes would likely have stopped the event.

These are real contributions. RCA reframes an outcome from a single person’s mistake to a system that produced conditions for failure, which is often closer to the truth of how modern healthcare harm occurs.

Now the limits, which matter just as much.

RCA identifies contributing factors and preventability. It does not, by itself, establish legal causation. The legal question of whether a specific breach more likely than not caused a specific injury is a different inquiry, governed by different standards, and it cannot simply be read off an RCA. Treating a root cause finding as proof of legal cause overstates the method.

RCA is also, in its native setting, a quality-improvement tool. Institutions conduct it to learn and to prevent recurrence, sometimes under legal protections that vary by jurisdiction. Its purpose there is improvement, not the assignment of legal fault, and that purpose shapes how it is conducted and what it concludes.

And RCA depends on the quality and completeness of the information behind it. An analysis built on a partial record can reach a confident conclusion that fuller evidence would revise. This is one reason accurate reconstruction of the record, including the system evidence the printed chart omits, should precede any strong causal claim.

For counsel, the practical posture is to value RCA for what it genuinely offers and to resist over-reading it. It can surface latent system conditions that a chart review alone would miss. It can frame preventability. It can organize a complex event into an understandable sequence. It cannot substitute for the causation analysis the case actually requires, and presenting it as if it can invites a credible challenge.

The honest use of root cause analysis is the disciplined use. It explains how a system failed and whether the failure was preventable, stated as what it is, and it leaves the distinct question of legal causation to be established on its own terms.