The CEDAC Approach

CEDAC is an acronym for cause-and-effect diagram with the ad­dition of cards.21 It was originally developed by Dr. Ryuji Fukuda of Sumitomo Electric, a Japanese manufacturing firm. Its pur­pose is to facilitate continual improvement in the workplace.

CEDAC is based on the supposition that three condi­tions must exist in order for continual improvement to occur. Fukuda explains these conditions as follows:22

  • A reliable system. For continual improvement to occur, there must be a standardized, reliable system. A system that is reliable will yield the same results regardless of who uses it, provided it is applied properly and according to standard procedures.
  • A favorable environment. Continual improvement will not occur unless an environment favorable to it exists. The keys to creating and maintaining an environment favorable to continual improvement are leadership and education. Leadership manifests itself in the form of commitment, both to the concept of continual improvement and to the allocation of the necessary resources. Education is how em­ployees become skilled in the use of the improvement sys­tem. The higher the density of employees who are skilled in the use of the improvement system, the better. Density is expressed as a percentage (see Figure 19.7).
  • Practicing as teams. Like all endeavors requiring skills, continual improvement strategies must be practiced. Because in a total quality setting work is performed by teams of employees, it is important for team members to practice together.

As teams practice, it is important for individual mem­bers to understand that improvements may come only in small increments. This is not merely acceptable; it is also desirable. In a competitive situation, the difference between winning and losing is often quite small.

In the United States, instant replay of sports events and big plays broadcast during the sports portion of the nightly news have accustomed people to last-minute game-winning home runs in baseball, desperation baskets just before the buzzer in basketball, and clock-beating 60-yard touchdown passes in football. What the camera does not show is all of the small, incremental improvements that put these teams in a position to win with one dramatic play in the final seconds of the game. This is unfortunate because a home-run mental­ity can mitigate against an organization’s ability to make the small incremental improvements that can mean the differ­ence between winning and losing.

The CEDAC system can be divided into two main parts (see Figure 19.8). Each part is subdivided into several re­lated activities. In part 1, a problem is identified. Quality tools such as those explained in Chapter 15 are used, as are additional quality tools, to analyze the problem. Based on the analysis, solutions are implemented in part 2. Results are monitored and confirmed. If the results are positive, the procedures that solved the problem are standardized, and these new standard procedures are followed by all employ­ees. If the desired results are not achieved, the team returns to part 1 to analyze the problem again.

 

Developing a CEDAC Diagram

Figure 19.9 summarizes the main steps in developing a CEDAC diagram.23 Instructions for these steps are con­tained in the following paragraphs:

  1. Draw the basic diagram. The CEDAC diagram should be drawn with the cause side on the left and the effect side on the right. Using CEDAC is a team activity. Consequently, the basic diagram should be large enough to attach to a wall so that it can be reviewed by team members at any point in the process. The cause side is a fishbone diagram with the addition of cards to the left of each spine. The effect side can be any of the various tools explained in Chapter 15 (e.g., a control chart or a Pareto chart). Figure 19.10 is an example of a basic diagram laid out but not yet containing any information. Such a dia­gram might be as large as 4 x 6 feet or even larger.
  1. Select the focus of improvement efforts. What is the focus of the CEDAC project? What problem is to be at­tacked? Quality tools such as those covered in Chapter 15 can be used to identify the improvement that has the most potential.
  2. Name a project leader. A CEDAC diagram relates to one specific improvement project and should have its own project leader. This is the person responsible for organizing, facilitating, monitoring, and completing the project.
  3. Establish a measurement method. Improvements tried as part of the CEDAC process should result in improvements on the effect side of the diagram. These results must be measurable. Does the improvement decrease waste? Improve throughput? Reduce de­fects? These are improvements that can be measured. Regardless of the focus of the project, establish mea­sures for documenting success or failure.
  1. Establish an improvement goal and date. The im­provement goal and projected target date are established by the project leader. It is important for this person to communicate why the goal and target date are important by relating them to the organization’s ability to compete.
  2. Format the effect side of the diagram. The actual format for the effect side of the CEDAC diagram must be decided on at this point. The preliminary chart pre­pared in the first step must be finalized. It can be a Pareto chart, a histogram, a control chart, or any other type of quality tool. The actual format selected should be the one that best communicates the necessary facts relating to the project. Figure 19.11 is a format that might be used if the project goal is to reduce throughput time by 50% over a 24-week period or any similar goal.
  3. Collect fact cards for the cause side. The goal is to re­duce throughput time by 50% within 24 weeks. All mem­bers of the project team should examine the problem and commit their ideas as to why throughput time is as high as it is to cards (e.g., 3 x 5 cards). These cards are known as fact cards. The fact cards should be sorted into general categories (material, manpower, methods, etc.). After all cards have been sorted into categories, the spines on the cause side of the CEDAC diagram are labeled to corre­spond with these categories. Cards in each category are examined and combined where appropriate. Remaining cards are then attached to the left of the horizontal lines along the spines, as shown in Figure 19.10.
  4. Collect improvement cards. Each fact card attached to the CEDAC diagram contains a description of some factor that contributes to increased throughput time. Each of these factors should be eliminated. To do this, improvement cards are collected from members of the project team. These cards correspond to the fact cards and contain a recommendation for eliminating the factor described on the corresponding fact card. Improvement cards are attached to the right of the hor­izontal lines along the spines, as shown in Figure 19.10.
  1. Implement and test improvement ideas. Improve­ment ideas should be carefully evaluated for credibility before being attached to the CEDAC diagram. However, after an improvement card is attached, the idea it con­tains should be implemented and the results monitored and recorded on the effect side of the diagram.
  2. Select cards for standardization. Improvement ideas that fail to reduce throughput time (see Figure 19.11) should be discarded. Those that work best should be written in as standard procedures in the process in ques­tion. After an idea is standardized, it should be adhered to strictly by all personnel.

Source: Goetsch David L., Davis Stanley B. (2016), Quality Management for organizational excellence introduction to total Quality, Pearson; 8th edition.

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