What is it: A Check Sheet is a structured, prepared form for collecting and analyzing data. The Check Shet is a generic tool that can be adapted for a wide variety of purposes. 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. A defining characteristic of a Check Sheet is that data is recorded by making marks ("checks") on it. A typical Check Sheet is divided into regions, and marks made in different regions have different significance. Data is read by observing the location and number of marks on the sheet. 5 Basic types of Check Sheets :
- Classification : A trait such as a defect or failure mode must be classified into a category.
- Location : The physical location of a trait is indicated on a picture of a part or item being evaluated.
- Frequency : The presence or absence of a trait or combination of traits is indicated. Also number of occurrences of a trait on a part can be indicated.
- Measurement Scale : A measurement scale is divided into intervals, and measurements are indicated by checking an appropriate interval.
- Check List : The items to be performed for a task are listed so that, as each is accomplished, it can be indicated as having been completed.
The Check Sheet is one of the seven basic tools of quality control, which also include the histogram, Pareto chart, control chart, cause-and-effect diagram, flowchart, and scatter diagram.
Why use it: Check Sheets are used to determine how often an event occurs over a designated period of time. Information may be collected either for events as they happen or for events that have already occurred. The overall intent and purpose of collecting data is to either control the production process, to see the relationship between cause-and-effect, or for the continuous improvement of those processes that produce any type of defect or nonconforming product.
Although the purpose of a Check Sheet is to track data - not analyse it, Check Sheet often helps to indicate what the problem is. Common items noted on Check Sheet are;
- Number of times something takes place,
- Length of time it takes to get something done,
- Cost of a certain operation over a period of time,
- Frequency of Occurrence; by machine, by employee, by location, etc.
Where to use it: Usually performed at the enf of production process.
When to use it:
- When data can be observed and collected repeatedly by the same person or at the same location.
- When collecting data on the frequency or patterns of events, problems, defects, defect location, defect causes, etc.
- When collecting data from a production process.
- Production process distribution checks - where the distribution lies.
- Defective item checks - to determine what kind of defects exist in the process.
- Defect location checks - to determine where the common defects on a part are located.
- Defective cause checks - type of defect and thus validate the cause thereof.
- Check-up confirmation checks - final phase of assembly to check the finished product or work.
How to use it:
- Decide what event or problem will be observed. Develop operational definitions.
- Decide when data will be collected and for how long.
- Design the form. Set it up so that data can be recorded simply by making check marks or Xs or similar symbols and so that data do not have to be recopied for analysis.
- Label all spaces on the form.
- Test the check sheet for a short trial period to be sure it collects the appropriate data and is easy to use.
- Each time the targeted event or problem occurs, record data on the check sheet.