The cause-and-effect diagram was initially developed by Japanese quality expert Professor Kaoru Ishikawa. In fact, these diagrams are often called Ishikawa diagrams; they are also called fishbone charts for reasons that will become obvious when we look at an example. Cause-and-effect diagrams are usually constructed by a quality team. For example, the team might consist of service designers, production workers, inspectors, supervisors, quality engineers, managers, sales representatives, and maintenance personnel. The team will set up the cause-and-effect diagram during a brainstorming session. After the problem (effect) is clearly stated, the team attempts to identify as many potential causes (sources of process variation) as possible. None of the potential causes suggested by team members should be criticized or rejected. The goal is to identify as many potential causes as possible. No attempt is made to actually develop solutions to the problem at this point.
After beginning to brainstorm potential causes, it may be useful to observe the process in operation for a period of time before finishing the diagram. It is helpful to focus on finding sources of process variation rather than discussing reasons why these causes cannot be eliminated. Cause effect diagram is used to assist teams in categorizing the many potential causes of problems or issues that may exist in Business or even in day to day life, in an orderly way and in identifying root causes. As problems come in many shapes and sizes, fishes also come in such an amazing variety of shapes and sizes that there is no ‘typical’ fish skeleton, so the Fishbone can be of any shape and size.
The causes identified by the team are organized into a cause-and-effect diagram as follows: 1. After clearly stating the problem, write it in an effect box at the far right of the diagram. Draw a horizontal (center) line connected to the effect box 2. Identify major potential cause categories. Write them in boxes that are connected to the center line. Various approaches can be employed in setting up these categories. For example, Figure below is a cause-and-effect diagram for “discourteous customer service” like in the video.
This diagram employs the following categories such as policy, procedures, people, and physical Environment 3. Identify sub causes and classify these according to the major potential cause categories identified in step 2. Identify new major categories if necessary. Place sub causes on the diagram as branches. 4. Try to decide which causes are most likely causing the problem or defect. Circle the most likely causes. After the cause-and-effect diagram has been constructed, the most likely causes of the problem or defect need to be studied. It is usually necessary to collect and analyze data in order to find out if there is a relationship between likely causes and the effect.
The situation shown in video is explained through fishbone diagram above. The analysis begins from high number of turnover which leads to deficiency of worker. It makes the services becoming slower and not efficient. In the video, one staff has the responsibility to serve food and phone reservation which will create confusion in busy time when all customers’ orders happen simultaneously. Another analysis shown in fishbone diagram is related to policy. The company policy states that the staff needs to input phone reservation to the computer which requires significant time to be verified. Procedures and physical environment are also two things that essential to be analyzed.
Procedures reflect there is no training as standard to handle certain situation in restaurant. In addition, hierarchy in the company creates environment where staff is reluctant to communicate with supervisor. This condition should be eliminated to encourage more communication between staffs and supervisor. On the other hand, physical environment is related to the space where customer encounters service. It can be classified as table layout, interior design, and so on.
The scenario performed in video is showing the idea that some table are far from kitchen which takes time to deliver the order. Therefore, some order might have time lead more than another table which is not placed far from kitchen. In brief, fishbone diagram is used for several purposes such as: * The team needs to study a problem to determine the root cause * Want to study all the possible reasons why a process is having difficulties, problems, or breakdowns in the initial stages of the process. * Need to identify areas for data collection
* To study why a service process is not performing properly and/or producing the expected results