Often referred to as fishbone diagrams,The Ishikawa diagram was created by Kaoru Ishikawa that show the causes of a specific event.
Common uses of the Ishikawa diagram are product design and quality defect prevention to identify potential factors causing an overall effect. Each condition or reason for imperfection is a source of variation. Conditions are usually grouped into major categories to identify and classify these sources of variation.

The diagraming process is derived from the quality management process, it’s an analysis tool that provides a systematic way of looking at effects and the causes that create or contribute to those effects. Because of the function of the fishbone diagram, it may be referred to as a cause-and-effect diagram. The design of the diagram looks much like the skeleton of a fish, hence the designation “fishbone” diagram.

Basic Ishikawa Diagrams are made up of four major categories, most typically Man, Machine, Materials, and Methods. The more complex versions of this tool can incorporate more major categories depending on the nature of the problem and factors that could impact a process.

Major Categories

You must assign the right worker to a job. The worker should be able to maintain good relations with other workers when working on group projects. Workers must be qualified to do the work to which they are assigned and have appropriate experience. They must follow the standards set for their activities and their efficiency must be acceptable. They must be problem-conscious; that is, they must stay alert to the potential for waste and take responsibility for seeking solutions to problems.

Your equipment or facilities must be adequate for the job, both in capacity and capabilities. If there is enough of the right type of equipment to do the job, ensure it is in working order or procure additional equipment to handle an excess load. If equipment problems can interrupt the process, consider using suitable machinery that does not require frequent adjustment. If the equipment requires precision adjustments, make the adjustments in a timely manner. Equipment that requires fuel, lubrication or inspection must be adequately fueled and lubricated, and required inspections must be kept up-to-date.

Quality standards for materials must be adequate, and you must check the materials as they arrive from the supplier for impurities, irregularities, damage or waste. While kaizen proposes minimizing the number of suppliers, this allows a supplier’s quality problems to propagate through your system. Several companies that relied on a single suppler for materials or systems, including Boeing, Caterpillar and Toyota, sustained significant difficulties when those materials and systems failed. An adequate supply of the correct materials is essential to sustain the service or manufacturing process. Workers and management must also make adequate provision for storage and material handling.

In evaluating methods, you must determine whether the work standards are adequate and safe. You must find an efficient method that provides a good product. The sequence of the steps used in the work must allow for the most efficient assembly of the product or for providing the service efficiently. The physical setup of the work area – whether a desk or a factory workstation – should maximize the flow of the project, and there should be sufficient lighting and ventilation for workers to perform their work efficiently. Arrange workstations so that the work flows evenly with a minimum of disruption and adequate communication.

GEOTECK technicians often implement this diagramming technique with clients when troubleshooting problems – especially reoccurring issues that can cut into our customers profitability and efficiency.