The power behind product process improvement and problem solving are the tools used for that specific end. So, over the coming months, we’ll be profiling 7 tried-and-true Quality Tools. The renowned Dr. Kouro Ishikawa, arguably the father of quality in Japan and originator of the Ishikawa ‘Cause and Effect’ Diagram, stated “As much as 95% of quality related problems in the factory can be solved with 7 fundamental quantitative tools.” Whether you are new to quality or involved for many years, a revisit and discussion of these fundamental tools is always beneficial. Please engage our experts as we present problem solving methods – ask a question, give examples, and/or comment in general. We welcome your involvement.
We will begin with Check Sheets. This tool is valuable to the data gathering process and enables the use of other tools such as Histograms and Control Charts through collection of data that can begin the statistical analysis process.
What is it?
First, what it’s not – some argue that a Check Sheet is not a Checklist. While a valuable tool in itself, a checklist is just that – a ‘check’ the ‘list’ of items/processes that need to be done. Key items of a process can be documented and used to ensure the repetitive quality of the operation. This is especially done when there are steps in the process that are critical to the final output of the product or service – mistake proofing. For example, a QMS audit checklist is used to ensure that all parts of the standard are considered.
However, a Check Sheet is a simple but powerful qualitative or quantitative data gathering tool, which can readily be analyzed to divulge useful information. (For a quick explanation of the difference between ‘qualitative’ vs. ‘quantitative’, see the reference below.2)
There are some basic types of Check Sheets that are useful in producing the raw data necessary for defect problem solving and further statistical analysis. Understanding the intended use of each will assist in selecting the appropriate one for the problem being analyzed.3
Process distribution check sheet5
This check sheet serves as a useful data gathering tool when observing process variation over time.The data gathered can feed into a Histogram analysis (more about that later…).
Defect type sheet
When a product or process contain a variety of defects, this type of check sheet is useful in categorizing the different defects and their frequency.It becomes evident which are the biggest sources of defects and prioritizing the opportunities for improvement. This is a simple example. However, consider the manufacture of an electronics printed circuit board. With hundreds of potential defects, a check sheet of defect type and frequency could be invaluable for establishing a plan for process statistical analysis.
Defect location sheet
This check sheet is similar to the defect ‘type’; however, the application is for analyzing where, or location, a defect occurs.In the same manner, a chart of where the defect occurs on a part can be developed.In this example, a defect type and location check sheet is developed to discover and remove the main causes of blemishes on a door.
Defect cause sheet
In the same manner as above, the attempt is to correlate defects with causal factors, which can be useful when root cause analysis is required.
Of the 7 Quality Tools, the Check Sheet is most likely the simplest tool to deploy but just as powerful as a product/process improvement technique. It should be considered for raw data gathering. Whether you are analyzing the frequency, location, and/or cause of a defect, simple data gathering can lay a foundation for further statistical techniques.
The Quality Tools are taught in our Q101 Fundamentals class coming up in November 2019.
We hope to see you there!
1Building from the Basics, Quality Progress Publication by ASQ, 2009
2Qualitative vs. Quantitative data – What’s the difference | learn.g2.com
35 Basic Types of Check Sheets | shmula.com
5Process Distribution Check Sheet | syque.com