Posts in category Methodology

Six Sigma strives to prevent process variation because variation hinders a process’s ability to reliably and consistently deliver high-quality products or services. The Design of Experiments (DOE) method allows quality …

Every step in the Six Sigma methodology pursues a solution that improves the organization’s processes and the quality of its product or service. In some projects, the DMAIC methodology will …

Cause-and-effect diagrams are one of the tools that Six Sigma professionals use to obtain the perspectives of individual members of a project team. The cause-and-effect diagram is a graphical brainstorming …

The first step of the Define phase of Six Sigma’s DMAIC methodology involves defining a project by creating a project charter. The project charter is a written document that captures …

The following table will convert Defects Per Million Opportunities to a Sigma Level.

Brainstorming is a method for generating a large number of creative ideas in a short period of time. Brainstorming is full of energy, moves rapidly, and is synergistic, creating a large list of ideas which may eventually be boiled down, or funneled down, to a smaller list of priority items later in the project.

Histograms are used to show the distribution of a set of collected data.

Generic bar charts can be created for any type of categorical or numerical data. If the categories of the data plotted in a bar chart have no meaningful order, many different charts can be created by rearranging the order of the bars. Histograms, on the other hand, are used to show the pattern or the distribution of the data across the categories, so there must be only one correct pattern.

The choice of Cell Intervals (the number and width of the classes used to construct a histogram) can have an effect on the shape of the histogram. In general, a smaller number of intervals results in a less distinct shape, while a larger number of intervals can reveal unexpected patterns.
Note: Please refer to the other topic on cell intervals for more information about rules-of-thumb in regard to cell choices.

When constructing a histogram (a graph in which the classes are identified on the horizontal axis and the class frequencies are shown on the vertical axis by the heights of the vertical bars) it is important to choose an appropriate number of Cell Intervals (the grouping you will use to generate the classes for the histogram).

The Check Sheet is a simple document that is used for collecting data in real time and at the location where the data is generated. The document is typically a blank form that is designed for the quick, easy, and efficient recording of the desired information, which can be either quantitative or qualitative. When the information is quantitative, the check sheet is sometimes called a tally sheet. The check sheet is one of the seven basic tools of quality control made popular by Dr. Kaoru Ishikawa.