Root Cause

In root cause analysis terms, a root cause is the deepest cause in a causal chain (or the most basic cause in a feedback loop structure) that can be resolved with practical solutions, without side effects that create other equal or bigger problems. A root cause is resolved by changing something in the problem system.

Resolved means the problem will probably not recur due to that root cause. If no resolvable root cause can be found, the problem is unsolvable. If this is the case, the problem definition can sometimes be relaxed to make the problem solvable, such as raising the maximum allowable global temperature rise for the climate change problem to make the problem solvable.

Here's a deeper, more profound definition. In systems thinking terms, a root cause is that portion of a system that, at the fundamental level, explains why the system’s natural behavior produces the problem symptoms rather than some other behavior.

A causal problem occurs when problem symptoms have causes, such as illness or a car that won’t start. Examples of non-causal problems are math problems, scientific discovery problems, information search/organization problems such as criminal investigation, and puzzle solving.

All causal problems arise from their root causes. This leads to:

Our Fundamental Principle

The only way to solve a difficult causal problem
is to resolve its root causes.

This principle lies at the very core of our approach. It drives everything we do. It's the fundamental way we think and work.

A few examples

All causal problems arise from their root causes, so examples are everywhere:

A car won't start. Why won’t it start? The intermediate cause might be a dead battery. The root cause might be a bad alternator, which fails to charge the battery. Replacing the battery will solve the problem temporarily. Replacing the alternator solves the problem permanently.

Suppose you have a persistent fever and a runny nose that won't go away on its own. Usually the root cause is an infection, easily cured with antibiotics. If the antibiotics don't work, that indicates that infection is an intermediate cause. The deeper cause (which is the root cause) might be a weakened immune system. Solutions to resolve the root cause might be eating a balanced diet, getting enough sleep and exercise, etc.

The root cause of the shortage of food problem during Homo sapiens' hunter/gatherer stage was total dependence on what the environment naturally provided. The root cause was resolved by invention of agriculture.

The intermediate cause of the 1986 Challenger space shuttle explosion was failure of the O-ring seal in a rocker motor, due to unusually cold temperatures. The cause of launching despite engineers' warnings that it was too cold to launch was managerial pressures to not postpone the launch. The root cause was political pressures causing organizational dysfunctionality. Richard Feynman "summed up the root cause: 'For a successful technology, reality must take precedence over public relations, for nature cannot be fooled.' "

Many root causes are simple. The root cause of a hole in your shoe is the shoe has worn out. The root cause of your getting wet while it's raining is there is nothing (like an umbrella or a roof) between you and the falling rain. Root causes like these are easily found and resolved.

Some root causes are not easy to find. Consider the famous Jefferson and Lincoln Memorials problem. The exterior stone surface on both memorials was eroding at an unusually fast rate. Using the Five Whys of Kaizen technique for finding root causes, the problem was solved in this manner:

1. Why is the memorial eroding? – Because it is being washed frequently

2. Why is it being washed frequently? – To remove bird “leavings”

3. Why are there bird leavings here? – Because the birds are hanging around

4. Why are birds hanging around? – They are eating spiders

5. Why are there spiders here? – They eat bugs

6. Why are there bugs? – They are attracted by the lights at dusk and dawn (root cause)

Solution – Turn the lights on only after dusk and before dawn.

The solution was implemented for six weeks. However, the public strongly objected since they could no longer take dramatic photos after sunset using the Jefferson Memorial as an iconic background. This led to further root cause analysis. The final solution was a mixture of solution elements, including removal of the accumulated biofilm, change to less harmful cleaning methods, wires and other items to keep birds away, and so on.

The five characteristics of a root cause

Earlier we said a root cause is the deepest cause in a causal chain (or the most basic cause in a feedback loop structure) that can be resolved with practical solutions, without side effects that create other equal or bigger problems.

This popular definition is not good enough for rigorous analysis. When you roll up your sleeves and begin analyzing a difficult problem, especially one with multiple root causes, the above definition is too loose. It provides no more than general guidance. What we need is a tight working definition, one we can constantly refer to as we seek root causes. Accordingly, has developed the following definition. A root cause has these identifying characteristics:

1. It is clearly a major cause of the problem symptoms.

2. It has no productive deeper cause. The word “productive” allows you to stop asking why at some appropriate point in root cause analysis. Otherwise you may find yourself digging to the other side of the planet.

3. It can be resolved. Sometimes it’s useful to include unchangeable root causes in your model for greater understanding. These have only the first two characteristics.

4. Its resolution will not create bigger problems. Side effects must be considered.

5. There is no better root cause. All alternatives have been considered.

The first three characteristics were published in Change Resistance as the Crux of the Environmental Sustainability Problem. In the spirit of continuous process improvement, two more have been added. The list of five characteristics is designed to serve as a checklist that you can use to quickly eliminate all sorts of things that are not root causes, but are intermediate causes or not causes at all.

Now let's examine:

Problem solving map

Where root causes fit in the Problem Solving Map

A problem's root causes is the main feature of the map. The map leads you from problem symptoms to their intermediate causes. The map says don't stop there and try to solve the problem with superficial solutions because that can't work. You must go beyond the superficial layer to the fundamental layer. This requires the use of the right analytical tools. Once in the fundamental layer you can find the root causes of the problem and their fundamental solutions.

The hardest part is penetrating from the superficial layer to the fundamental layer. Few environmentalists, even scholars, are used to doing this. They have been dwelling on the superficial layer for decades, as shown by superficial solutions like carbon taxes, the Kyoto Protocol, many pollution laws, and sustainable life cycle product design. While these are helpful, they are not nearly enough to resolve the intermediate causes, because those are caused by root causes.

Problem solvers around the world persist with superficial solutions that repeatedly fail because they "know" the intermediate causes are the root causes. This false assumption arises because they cannot see the fundamental layer. It's invisible.

Hopefully that will change once they have the Problem Solving Map.

An application example using the checklist

Popular consensus sees things like the four factors of the IPAT equation, the human system’s growth loops, economic inequality and poverty, and lack of cooperation and other maladapted values as the root causes of the environmental sustainability problem, when in fact they are intermediate causes.

A broad and revealing example of this consensus comes from James Gustave Speth (cofounder of the Natural Resources Defense Council, founder of the World Resources Institute, and administrator of the United Nations Development Programme for six years), who wrote that: 1 (bolding and comments added)

The [five] transitions I will mention briefly seek to deal with the root causes of environmental problems. … The first transition …is the need for a demographic transition to population stability [the P in the IPAT equation] … The second transition is… a transition in technology to a new generation of environmentally benign technologies [the T in the IPAT equation] … The third needed transition is an economic transition to a world in which prices reflect the full environmental costs [a balancing loop to put the brakes on the reinforcing growth loops of the IPAT factors, mostly the A and T, by internalizing externalized costs] … The fourth transition is a transition in social equity to a fair sharing of economic and environmental benefits both within and among countries. Over much of the world, the greatest destroyer of the environment is poverty—because the poor have no alternative. … None of these transitions is possible without a fifth—an institutional transition to different arrangements among governments, businesses, and peoples. These institutional arrangements are urgently needed to enlist the tremendous potential of the private sector in what must be an unprecedented cooperative effort….

James implies five root causes: population growth, lack of environmentally benign technologies, lack of prices reflecting full environmental costs, poverty, and lack of cooperation. Using the checklist of the five characteristics of a root cause, we immediately see these are pseudo root causes. They all have the first characteristic, "It is clearly a major cause of the problem symptoms." But they all lack the second characteristic, "It has no productive deeper cause." For each of the five so called root causes James has listed, you could ask these questions:

1. WHY is it so hard to quickly put the brakes on global population growth by, for example, changing to a worldwide one-child-per-family policy for several generations?

2. WHY are technologies increasingly harmful to the environment?

3. WHY is the system so biased towards externalizing costs?

4. WHY isn’t the industrialized world already taking care of those less well off?

5. WHY aren’t governments, businesses, and peoples already cooperating?

Questions like these demonstrate these are in fact intermediate causes. They are mere starting points for deeper analysis.

This is a prime example of how:

There are a thousand hacking at the branches of evil
for one who is striking at the root.


(1) The quote is from The transition to a sustainable society by James Gustave Speth, 1992. It was published in Proceedings of the National Academy of Sciences, USA, Vol 889, pp. 870-872. February 1992.

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The Law of Root Causes

If you're working on a difficult problem, then you can increase your chance of solving it by an order of magnitude by adopting The Law of Root Causes.

How to Change a Problem from Impossible to Solvable So You Can Find Its Root Causes

This can be done by the right analysis. Analysis is breaking one big problem down into the right smaller subproblems, each of which is much easier to solve by finding and resolving its root causes. If the right subproblems are chosen, this can change a difficult problem from insolvable to solvable because you are no longer trying to solve all the subproblems simultaneously without realizing it.

Multiplication exampleA simple example is multiplication by hand. Suppose you need to multiply two three digit numbers. Only a few geniuses can do it in their head. The rest of us need to do it on paper by multiplying two single digit numbers at a time. This divides the problem into nine multiplication subproblems followed by five addition subproblems, a decomposition that has changed solving the problem from impossible to easy.

The sustainability problem can be changed from impossible to solve to possible by dividing it into the right four subproblems.

How Are Root Causes Found?

If it's an easy problem, by a quick look at the problem and rapid development of the solution using techniques like creativity, brainstorming, crowdsourcing, literature review, and expert opinion.

If it's a difficult problem that won't work because no true analysis is performed. The only known way to reliably solve difficult complex system problems is root cause analysis.