A commonly used six sigma tool for collecting data in the evaluation stage is a checklist, also known as a questionnaire. The purpose of the checklist is to collect data on process performance to be improved. The unified format of the checklist is usually a table, and the design of the checklist should be as simple as possible and conform to the characteristics of evaluation. The specific form of the list depends on whether the collected data is continuous or discrete. Generally speaking, the checklist of discrete data is simpler than that of continuous data, because the checklist of discrete data is mainly based on technology.

There are four commonly used lists:

1, record list

Record list is also called nonconforming list. It can record the frequency of several features in a period of time, or the frequency of various defects in several batches of the same type of products.

2. Distribution list

Distribution checklist, sometimes called quality distribution checklist or production process checklist, is used to record the distribution of a certain quality characteristic value of a product.

3, defect location investigation

If the defect type of a product is related to its location on the product, the defect location list can be used at this time. The defect location checklist can intuitively reflect the location and density of various defects.

4, defect reason checklist

The defect cause list, also known as matrix list, is used to find out the causes of defects. The checklist also requires that the types and representative symbols of defects be determined in advance, and then the equipment, operators and working hours corresponding to the production process are used as horizontal and vertical headings respectively. During the investigation, record all kinds of defects and their quantity on the crossbar.

In the six sigma improvement method, the checklist provides a good foundation for improvement. As can be seen from the table below, paint is the most common source of defects.

Checklist

In addition to collecting data directly, checklists can also be used to confirm the distribution of processes and the frequency of continuous data. Making inventory is an effective tool to collect the data needed in the evaluation process. Storing the inventory in the computer can save a lot of time and resources, and help to make better use of these data in the next stage of analysis.