The Psychology of Quality and More
The Check Sheet
Charles Dickens’ Uriah Heep is famed for his ‘Ever so ‘umble’ way of talking and perhaps would be proud of the simple Check Sheet, one of the original ‘First Seven Tools for Quality Control’.
Check Sheets come in all shapes and disguises, being simply any organised way of collecting manual information.
How it works
Writing things down on the back of an envelope, a cigarette-packet or, more recently, a Post-it Note, is a common way of collecting information. However, if this collection is a part of managing the business or improving quality, something more organised can not only increase the reliability of the data, it can also save time in creating data and charts that are immediately useful.
The simplest form of Check Sheet is the Tally Chart, where ‘tally’ means to count. In this, check marks are used to count events, often in the form of ‘five-barred-gates’.
A second form of Check Sheet is the Location Plot or Concentration Diagram, where a picture of the item being examined is drawn and the location of problems are marked on the diagram. A variant of this that can be used when improving the use of forms (for example where people do not fill the form in properly) is simply to tear off a form and mark on this where incoming forms are incorrectly used.
Another form of Check Sheet is the Check List, which checks that items have been completed, rather than counts problems. As such, it is a useful device to help error-proof processes and can also help simplify documentation. All you have to define as a standard is that the checklist is used.
A final example of a Check Sheet format is to build charts such as a Histogram with the Process Distribution Check Sheet so you can see the performance of the process building up as you are using the sheet, without having to wait for later analysis.
Process Distribution Check Sheet
How to do it
1. Identify your situation and the quality measurement needs. For example, in improving the turnaround time of a delivery system, you may want to count the number of packages returned with various problem statuses, such as ‘address unknown’ or ‘nobody to accept package’.
2. Design the Check Sheet to collect the data. Make it easy to use both for collecting the data and also analysing and using it afterwards. Include information to allow each sheet to be uniquely identified, with fields for such as date, batch number, operator, etc.
3. Ensure that the people who are going to use the sheets know exactly how to use them. It is surprising how often what is blindingly obvious to you is less than clear to other people,.
4. Deploy and use the sheets, as planned.
Next time: Capability Index
This article first appeared in Quality World, the journal of the Institute for Quality Assurance
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