Why Ask Why?

A lesson on latent causes

by Rajeev Chadha

This article was featured in January 2016’s Best Of Back to Basics edition.

Five whys is a fundamental and simple method of root cause analysis (RCA). Asking "Why?" is formalized by some industries and is a favored technique of many reliability, Six Sigma and manufacturing professionals. By repeatedly asking the question "Why?" you can peel away layers of the symptoms that lead to a problem’s root cause. Often, the ostensible reason for a problem will lead you to another question. Although this technique is called five whys, you may need to ask the question fewer or more than five times before you find the issue related to a problem.

Some believe that there are five levels of causes: cause effect, physical cause, human cause, systemic cause and latent cause. If the cause is physical or human, it can be corrected easily. Systemic and latent causes, on the other hand, can only be influenced at the initial stage. Their corrective actions need top management interventions to change programs, policies and procedures.

We will focus solely on latent causes because identifying them early can prevent other organizational issues. Although intensive investigation and what may seem like a tedious amount of evidence collection may be required, these steps are imperative in earning managerial approval to proceed with corrective action.

Dealing with latent causes

At the organizational level, latent causes are the conscious decisions made regarding whether to do certain things. Most of the time, these causes do not include simple employee mistakes (such as forgetting a step in a process), nor do they include repercussions of inadequate training. These kinds of issues will be discovered and dealt with when probing for latent causes.

One automotive supplier addressed multiple customer complaints regarding a plastic molding die and eventually altered the die to resolve the issue. The die’s life cycle was ending, and the team was still tracing the root cause at the physical and human levels. The actual issue regarding the faulty plastic parts used in the die-holding containers was, in fact, the latent cause. The tool was old and needed to be replaced, but neither management nor the customer wanted to invest in the production of an entirely new tool.

Industrial latent causes are nothing new, but as an RCA specialist, it is important to encourage management to accept the reality of these causes so it can decide what corrective action is necessary.

A refinery chemical engineer approached me with one of his chronic issues that was causing big losses and countless customer complaints about the product quality. We did an initial five whys analysis (see Figure 1), and there were clear indications of a latent cause. The engineer got his answer as to why the product, though greatly under-specified, was still running.

Figure 1

As explained in the diagram, solving the physical root cause of the issue is not sufficient in many circumstances and that is why it is important to influence management about the latent and systemic causes of the problem you are tackling.

Organizational plans are the how-to documents that show how company operations are performed. If we want to know how the production, quality assurance, human resources or marketing in an organization will take place, the plan will explain those processes as well. So, to unfold the latent cause of a chronic organizational problem, you may need to involve upper management. The simplest approach is to develop an activity hierarchy and unveil the latent root cause so that management can change the operational plan.

As famous author Edward Hodnett once said, "If you don’t ask the right questions, you don’t get the right answers. A question asked in the right way often points to its own answer. Questions are the ABCs of diagnosis. Only an inquiring mind solves problems."

Rajeev Chadha is an industrial technology advisor for the National Research Council Canada in Alberta, providing advisory services in mining, manufacturing and chemical processes. He has a master’s degree in systems management from the Indian Institute of Technology Delhi in New Delhi. A senior member of ASQ, Chadha is a certified Black Belt, and quality engineer and auditor.

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