Posts in category Six Sigma

A matrix diagram is a tool that illustrates the critical relationships between or among two or more groups. It can be enhanced to show things like the strength of the relationship or the different aspects of the relationship.

A defect location check sheet (also known as a defect map or a measles chart) is a structured, prepared form for collecting and analyzing data that provides a visual image of the item being evaluated so that data can be collected visually rather than merely collecting a count of the number of defects.

The nominal scale is a measurement scale that lists names (categories.) Nominal data is discrete data and there is no particular order with a nominal measurement scale.
Think of going to your favorite fast food restaurant. For example, the restaurant manager might list the first names of the employees, or might list the models of the cars that they drive. These are examples of a nominal measurement scale. You could put the names in alphabetical order, but the names really have no meaning of the rank order. When you think of nominal, think of the word ‘name’ – both start with an ‘N.’

The nominal group technique (NGT) is a decision-making method used by teams to separate the vital few from the trivial many.

Separation of the important items from the not-as-important items can be made using various techniques. One technique is majority rule. The decision made by majority rule is quick, but those in the minority feel alienated because they lose. It is better to get a win-win decision. A popular nominal group technique is to give everyone on the team five votes. Some use Post-it notes where one note equals one vote. Each member can vote on one item and use all of their five votes on that one idea. The team member may choose to split his or her votes among a few different ideas. For example, they might want to put three votes on one idea and two votes on another idea. They might even want to put one vote on each of the five items.

To add value means that three things have occurred.

The process step has changed the form or function of a product or service
The customer is willing to pay for the change
The step is performed correctly the first time.

Any time in the process where value is not added is waste, also known as non-value adding.

There is no use for a non-value adding step, but it is essential that you can see it, reduce it, or completely eliminate it.

The reality in the world is that variation exists. If variation did not exist, if we made a product right the first time, every product would be right the first time. The same would hold for providing a service. But, the reality is that we live in a world where variation does exist and therefore every now and then we will have to deal with a defect, mistake, flaw, or error. Another reality is the variation can be random, meaning that no undue influence is coming from the people, the machinery, the materials, the methods, the measurements, or from the environment. If the variation in a process is random, it is at a state of normality. Other names for normality include common-cause, chance variation, and random variation.

The np chart is used when the data can only be whole numbers, as in counting, it is known discrete data (also known as attribute data). Every item in the sample is evaluated for only the number of defects, flaws, or occurrences, etc.

The np chart is used with a fixed sample size where you are counting the number of defectives in the sample. If you remember, the difference between a defect and a defective is this. A defect can be found on an otherwise acceptable product; whereas, a defective means that the whole item is unacceptable.

Ordinal is data that is arranged in order.

You might use the ordinal scale using numbers or symbols to rank order – by importance, by strength, by severity, etc. The intervals are unspecified (e.g., months of the year)

Dr. W. Edwards Deming used a four step process, which is more of a cycle – – PLAN, DO, CHECK, ACT for process improvement. The idea in the PLAN step is to define the process to improve. The DO step is implementing the plan and measuring its performance. The team then takes those measurements to assess whether they are getting the desired results. This is known as the CHECK step. The ACT step follows. The team decides on changes that need to be made to improve the process; then, the whole cycle starts again.

A pert chart is used to show activities that are in parallel and/or in series. It will show the most likely times, the most pessimistic times, and the most likely times for the completion of projects. Also known as activity network diagram, arrow diagram, and critical path method.