Real-World Project Management: Beyond Conventional Wisdom, Best Practices, and Project Methodologies

Chapter 12. The Seven Ishikawa Quality Tools

In his Guide to Quality Control, originally published by JUSE (Union of Japanese Scientists and Engineers) in 1968, Kaoru Ishikawa described seven quality tools that could be easily learned by employees in manufacturing.

Ishikawa maintained that if workers knew how to correctly apply these seven tools, 95% of all defects, variation, and inconsistency could be eliminated from any process. The seven tools are:

1. Histogram

2. Scatter diagram

3. Pareto chart (a specific type of histogram)

4. Ishikawa diagram (cause-and-effect ox fishbone diagram)

5. Statistical process chart

6. Flowchart

7. Checksheet

HISTOGRAM

The histogram is a vertical (or horizontal) bar chart that is used to show how data is distributed in a given set. It's like a snapshot—it shows data distribution or frequency of data at a given moment in time. Figure 12.1 is a histogram of ticket sales at a movie theater for one week.

Here is your snapshot in time, in this case called a frequency histogram because it shows you (1) the spread of the measurements and (2) how many of each measurement there are.

Why is the chart important to the business? What if you were investing in a movie theater chain and wanted to see how well the theater was doing—would you base your investment decision on one day's worth of ticket sales, Saturday's for example, or would you want to see how well the business did (1) on different days of the week, (2) at different times of the year, (3) with blockbuster first-run films, and (4) ...