Course Content
Business 315: Logistics & Supply Chain Management
    About Lesson
    Companies need tools to evaluate quality throughout their business processes. In this lesson, you will learn about the seven quality tools and how they help support operations management goals.

    Definition of Quality Tools

    Just as a construction team needs tools to build, operations and supply chain management departments need tools to evaluate quality throughout their processes. There are seven quality tools that are used to help support quality management goals by understanding and improving production processes.

    The tools are referred to by many different names in the business world, such as ‘The Old Seven’, ‘The First Seven’ and ‘The Basic Seven’. The father of the tools is Karoru Ishikawa, an engineering professor at Tokyo University who first came up with the list. Let’s take a look at some quality scenarios to see how each of the seven tools works with an aerospace company called Jets R Us.

    Cause-And-Effect Diagram

    The first quality tool that can be used to evaluate processes is the cause-and-effect diagram, also known as Ishikawa/fishbone chart. This diagram can be used to identify many possible causes for an effect or problem. The final results of the chart are vital to help structure a brainstorming session as it immediately sorts ideas into useful categories. This type of diagram can be very helpful for companies to understand the causes of everyday problems.

     

    Fishbone Chart
    fishbone chart

     

    Jets R Us begins the process for building a cause-and-effect diagram with a brainstorming session in a team environment. The problem is discussed and then all causes from each area of the problem are shown on the diagram. In this instance, Jets R Us is having an issue with a defect in their newest airliner. You can see an example of their cause-and-effect diagram with potential problem areas. Once the diagram is complete, the end result is usually further analyzed.

    Check Sheet

    Another method of evaluating processes for quality control is a check sheet, which is a real-time, structured form for compiling, recording and researching both observational and historical data. Jets R Us considers a check sheet the most basic tool for quality, and it can be tabulated and analyzed by simple software, such as Excel. Jets R Us uses one form of a check sheet exclusively to observe and note any finishing issues. Their tally sheet is a form of a check sheet and is used to make note of where any exterior issues are noted as the plane is heading for sale. For example, the tally sheet for plane 104 showed two areas of exterior finish issues on the right wing.

    Check Sheet
    Check Sheet

     

    Control Charts

    Control charts are also used by Jets R Us to monitor quality and study how a process changes over a time period. Control charts are most effective analyzing time series data. Each point on the chart represents a statistic, such as a range. The center line is then represented with the mean of the statistics in order to establish upper and lower control limits. Anything over or below the limits causes Jets R Us to investigate.

    Jets R Us uses them to help with analyzing performance in areas such as stability and predictability of the production process and to discover any variations in order to fix them. For instance, Jets R Us has been using control charts to monitor the number and percent of defects in their production process for the new small jet planes.

    Control Chart
    Control Chart

     

    Histograms

    Jets R Us also uses histograms as visual interpretation of numerical data by showing the number of data points that lie within a range of values, called a class or bin. The frequency of the data that falls in each class is represented by the use of a bar.

    Histogram
    Histogram

     

    The graph consists of columns that represent the distribution of the mean. If the histogram is not normal, it does not have a bell-shape curve. For example, Jets R Us uses histograms to analyze their production process for the planes. If a histogram does not result in a bell-shape curve, then there could be an issue in the manufacturing process.

    Pareto Chart

    Pareto chart is a vertical bar graph where values are shown in decreasing order of relative frequency from left to right. Pareto charts are detrimental for analyzing what problems need to be prioritized because the taller bars on the chart, which represent frequency, show which variable has the biggest impact on a process.

    Pareto Chart
    Pareto Chart

     

    The advantage of a Pareto chart is that it can determine which factors are more significant or to identify a set of priorities that could be the cause of company issues. Jets R Us uses the Pareto chart to illustrate issues related to employee absences and record the number of occurrences. Jets R Us was able to discover that traffic and childcare were the leading two issues that stood in their way for a productive day. This led to the company building an onsite daycare to fix the issue.

    Scatter Diagram

    scatter diagram is a type of diagram that reflects the relationship between data items that have two numeric properties. One property is shown along the x-axis and the other along the y-axis with every item characterized by a single point.

    Scatter Diagram
    Scatter Diagram

     

    A scatter diagram is also the best alternative for comparing two different variables and analyzing a cause-and-effect relationship. Jets R Us recently used a scatter diagram to compare temperature of the factory with total daily production output. The company found that the colder the factory floor temperature was, the more productive the workers were.

    Flow Chart

    The final quality tool is the flow chart, and it is a diagram that communicates steps through boxes and arrows to conclude with a solution to a specific problem. Jets R Us prefers flow charts to analyze their airplane production process and quality checks. For example, the company has their managers follow a flow chart to determine the potential reasons for issues on the production floor.

    Flow Chart
    Flow Chart

     

    Lesson Summary

    There are seven quality tools that are used to help support quality management goals by understanding and improving production processes. The seven tools are:

    • The cause-and-effect diagram, also known as Ishikawa/fishbone chart, can be used to identify many possible causes for an effect or problem. The final results of the chart are vital to help structure a brainstorming session as it immediately sorts ideas into useful categories
    • check sheet, which is a real-time, structured form for compiling, recording and researching both observational and historical data
    • Control charts are also used to monitor quality and study how a process changes over a time period
    • Histograms are visual interpretations of numerical data by showing the number of data points that lie within a range of values, called a class or a bin. The frequency of the data that falls in each class is represented by the use of a bar.
    • Pareto chart is a vertical bar graph where values are shown in decreasing order of relative frequency from left to right.
    • scatter diagram is a type of diagram that reflects the relationship between data items that have two numeric properties. One property is shown along the x-axis and the other along the y-axis with every item characterized by a single point.
    • The flow chart, which is a diagram that communicates steps through boxes and arrows to conclude with a solution to a specific problem

    Learning Outcomes

    By the time you are finished, you should be able to:

    • Name and describe the seven quality tools
    • Discuss the purpose for each tool