A. MARK DOGGETT, HUMBOLDT STATE UNIVERSITY
© 2005, ASQ
This article provides a framework for analyzing the performance of three popular root cause analysis tools: the cause-and-effect diagram, the interrelationship diagram, and the current reality tree. The literature confirmed that these tools have the capacity to find root causes with varying degrees of accuracy and quality. The literature, however, lacks a means for selecting the appropriate root cause analysis tool based upon objective performance criteria. Some of the important performance characteristics of root cause analysis tools include the ability to find root causes, causal interdependencies, factor relationships, and cause categories. Root cause analysis tools must also promote focus, stimulate discussion, be readable when complete, and have mechanisms for evaluating the integrity of group findings. This analysis found that each tool has advantages and disadvantages, with varying levels of causal yield and selected causal factor integrity. This framework provides decision makers with the knowledge of root cause analysis performance characteristics so they can better understand the underlying assumptions of a recommended solution. Key words: collaboration, decision making, problem solving, quality methods
Beneath every problem is a cause for that problem. In order to solve a problem one must identify the cause of the problem and take steps to eliminate the cause. If the root cause of a problem is not identified, then one is merely addressing the symptoms and the problem will continue to exist. For this reason, identifying and eliminating root causes of problems is of utmost importance (Andersen and Fagerhaug 2000; Dew 1991; Sproull 2001). Tools that help groups and individuals identify potential root causes of problems are known as root cause analysis tools. The cause-and-effect diagram (CED), the interrelationship diagram (ID), and the current reality tree (CRT) are three root cause analysis tools frequently identified in the literature as viable mechanisms for solving problems and making decisions. The literature provides detailed descriptions, recommendations, and instructions for their construction and use. Furthermore, the literature is quite detailed in providing colorful and illustrative examples for each of the tools so they can be quickly learned and applied. In summary, the literature confirms that these three tools are capable of finding potential root causes. Conversely, although there is much information about the individual attributes of these root cause analysis tools, there is little information regarding the performance of these tools relative to each other. Thus, problem solvers and decision makers are likely to select a tool based on convenience rather than on its actual performance characteristics. Thus, the purpose of this article is to explore and synthesize the current literature for a head-to-head performance analysis of the CED, ID, and CRT. The intent is to provide problem solvers with a mechanism that can be used to select the appropriate root cause analysis tool for the specific problem.
34 QMJ VOL. 12, NO. 4/© 2005, ASQ
Root Cause Analysis: A Framework for Tool Selection
The first section of this article presents an overview and a background of the CED, ID, and CRT. For each tool, there is a brief history, a presentation of various construction techniques, and a summary of the tool’s advantages and disadvantages. The second section reviews published articles that compare these tools. The third section analyzes the literature and provides a conceptual framework with a head-to-head comparison for problem-solving practitioners and decision makers. The final section concludes with implications and recommendations for management. Figure 1 Steps in building a cause-and-effect diagram.
Characteristic or effect A. Write the characteristic to be improved. Cause...