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Paul Naysmith

Quality Insider

Seven Quality Tools of an Improvement Ninja, Part 2

The check sheet

Published: Monday, February 11, 2013 - 13:57

If you haven't read part one of my Improvement Ninja series, don't worry. Unlike The Godfather Part II, you don't need to see the preceding installment to make sense of this article. I continue my journey to enlighten newly initiated quality colleagues by discussing the check sheet, which is the second quality tool of the seven recognized by the American Society for Quality (ASQ).

For those not in the know about the seven quality tools, they are:
1. Cause and effect diagram
2. Check sheet
3. Control charts
4. Histogram
5. Pareto chart
6. Scatter diagram
7. Stratification

Granted, I will probably struggle as I talk about check sheets, partly because they may seem so simple and obvious. They are, but sometimes we need to discuss the obvious because to some, it might not be.

Tool 2: The check sheet

I did a little research on check sheets and found that few people have written on the subject. There is a great deal of information about how to use check sheets, but I could find little on its origins or starting point in history. Personally, I've always used lists of some sort throughout my life, and that's perhaps why I like using the check sheet tool. I remember writing a list for Santa as a child, and as an adult my morning routine begins by creating a checklist of what I wish to achieve that day. I would even state that I enjoy watching those list programs on TV, not for their content but for how they use the lists.

I'm sounding supremely dull, rambling on about lists here... so my quality colleagues, if you're aware of any research on check sheets beyond what's here, please drop me a line and let me know.

We live in a world with information and data all around us. Assuming data is not living in a computer but is loose in the real world, we need an easy method for gathering these data, and this is where check sheets come into their own. Although they have many purposes, they are really helpful in enabling users to collect and analyze data at the same time.

Check sheet tool ratings:
Difficulty to understand. I rate the check sheet a 1 on a scale of 10, with 10 being most difficult. I believe that virtually anyone who can read or write in this world would easily understand this tool, and you would not have to explain it much.
Difficulty to use. I rate it a 1 out of 10, with 10 being the most difficult. If you can't count or write, you might find this a difficult tool.
Difficulty to create on a computer. I rate it a 2 out of 10, with 10 being the most difficult. As you will read below, you can create check sheets using many different software options.

How to create one

Borrowing heavily from Barrie G. Dale's book, Managing Quality (Wiley-Blackwell, 5th ed. 2007), there are six steps to creating a check sheet:
1. Determine what data need to be collected.
2. Decide which features, characteristics, and/or items should be checked.
3. Determine the type of check sheet that you should use.
4. Design the sheet.
5. Specify the format, instructions, and sampling method for recording the data.
6. Determine the time period during which data are to be collected.

In his 1974 book, Guide to Quality Control (Quality Resources, 2nd ed. 1986), Kaoru Ishikawa highlights five types of common check sheets. I presume that much of his work would have originated from manufacturing. However, I'll attempt to give examples of where I've used these check sheets elsewhere. And because I'm a lover of the list, here's one for Ishikawa's five:
1. Process distribution check sheet
2. Defective item check sheet
3. Defect location check sheet
4. Defect cause check sheet
5. Confirmation check sheet

Process distribution check sheet
The process distribution check sheet is a quick way to produce a histogram, or in nonstatistical terms, a bar chart that expresses the distribution of the values from a process. I have found this is a useful tool only if there is a huge amount of data around, over a period of time. It's a particularly useful way to create an expression of the process spread, and it can be seen at point of use rather than waiting for a data table to be filled in.

In figure 1 I have created an example of—don't laugh—the duration of time it takes me to travel to work in the morning using my in-car stopwatch. (I told you I liked check sheets... am I the dullest being on the planet?) As I set about making a table, I considered that the quickest I could get to work would be 10 minutes, the slowest 25 minutes, and I would put in a mark in the appropriate column after my drive. The results can be seen below.

Figure 1: Process distribution check sheet for Ninja driving time

My first observation based on this check sheet, other than I should consider using my time in a more effective manner, is that it offers a quick representation of my journey times. So knowing this, I can also see that it's not the individual data points that are important but the distribution form itself, or the shape of the graph. (I'll cover this in more depth when we look at histograms in part four of this series.)

Defect items check sheet
The defect items check sheet is the one I'm most familiar with. I certainly use it to reduce the number of defects in a process, and it's especially helpful for targeting types of defects. By listing the defects according to type, we can better use our limited and valuable time. The example in figure 2 is of a goods receipt or stores warehouse process. Whenever a worker sees a defect in a delivery, he makes a tally mark in the appropriate box for that day. That information is then given to the quality people and should be analyzed. I like to use quality tool No. 5, a Pareto chart, for this task, with the aim of gaining a better understanding of where to investigate to prevent repeat occurrences.

Figure 2: Receipt inspection defect check sheet

Defect location check sheet
The defect location check sheet is similar to a defect check sheet, but rather than a table format, this tool uses a picture to represent the defect's location. In some circles, a defect location check sheet is referred to as a "measles chart." The example in figure 3 is from a computer-based defect location check sheet. To create it, the inspector first presses the defect type on the touch screen, then presses on the picture where that defect is located. The software program counts the defect types and locations and can produce, in the same format, an image of where the locations and defects commonly present themselves. Again, as with the previous check sheet, this is a useful tool for reducing defects, especially since it allows you to target the most common fault first. You may have come across a similar check sheet when you rent a car, and the rental agent hands you an illustration of a car with the existing damages marked on it. Thus you can drive off safe in the knowledge that these defects won't be considered your fault when you return the car.

Figure 3: Defect location check sheet

Defective cause check sheet
The previous check sheets are useful for investigating defects, but as Improvement Ninjas, we must consider not only the effects or outcomes of defects but also their potential causes. The defective cause check sheet helps us gather further information about a cause, or it can show a relationship between different factors. The information from these check sheets can be applied later to quality tool No. 6, the scatter diagram. In the sample example in figure 4, a theory was formulated from defects produced in a production line. The theory was that a certain work shift was a factor that required investigation and measurement. The old "issues only happen with B shift" syndrome, as I call it.

From the data collected, it was apparent that there was, in fact, a "B shift" thing going on. Further studies and investigation dug deeper and identified that as afternoon heat would build up in the factory, it had an effect on the process on machine 1 in particular.

Figure 4: Defect cause check sheet

Confirmation check sheet
The last type of check sheet on Ishikawa's list is the confirmation check sheet. It definitely would be included in a list of lists I love. I create a confirmation check sheet every working day in my notepad. This is different from the previous four check sheets, which I use to capture quality characteristics such as defects. Figure 5 shows a check sheet used at a car mechanic’s shop as part of a safety check. This confirmation check sheet is used to check the status of the car’s various systems at specified intervals. As you can see, there are a dozen check items. The check sheet helps prevent the same check happening twice, or someone forgetting what to check in a particular order. Even the most absent-minded or distracted person can benefit from this tool. Because I sometimes fall in that category, I make a confirmation sheet every morning of all the objectives I aim for in my working day. What I don't achieve by quitting time will be on my list tomorrow. A confirmation check sheet also serves as a record that can be referred to later.

Figure 5: Confirmation check sheet for vehicle inspection

Helpful software for using the tool

MS PowerPoint. Great for making visual defect check sheets with photos or drawings. Figure 2 was produced using this software, and then the computer experts made it interactive for touch screens.

MS Word. Using the table button on the insert tab, you can easily create a check sheet like figures 1, 2, and 4 very quickly.

MS Excel. Great for creating a check sheet, Excel can also be used as a data analysis tool for creating charts. Excel is, in essence, a giant table, and I really like that I don't have to create one in Excel as I would in Word. Excel also makes it simple to turn check sheet data into gorgeous charts.

MS Visio. Like PowerPoint, this software is good for creating visual defect check sheets; however, it's a pain in the caboose for making tables, so I  don't use it for making other types of check sheets.

Minitab. Like Excel, Minitab is a great big table, so it's great for both making check sheets and analyzing data.

Hints and tips

Check items described as "other." Be cautious if you use "other" as a category in a check sheet. If you just capture "others" without defining what these are, your data may become diluted with meaningless information. If you have an "other" box, I suggest that you provide an area spacious enough to jot a description for the "others," then redesign the check sheet with the new characteristic.

Colored check sheets. If you use more than one check sheet in your business at the same time and in the same location, consider printing them on different-colored paper. This will help differentiate them for the data-collection process.

Pocket-sized check lists. I have designed confirmation check sheets throughout my career to help me gather data; however, I have usually relied on others to collect the data for me. With that in mind, I've found that a check sheet which fits neatly into the top pocket of a set of coveralls is more welcome than a sheet of paper the size of a modern wafer-thin TV.

Brainstorming check items. I like to create new check sheets, but I've found it's a good idea to bring in many differing stakeholders to help identify check items or come up with ideas about what needs to be checked.

Timeliness of checks or information. As with most data, if the check item is not captured or reviewed quickly, the knowledge and improvement opportunity it represents may be lost.

So there you have it, the second of the seven quality tools as seen by this Improvement Ninja. In the next installment, I will tackle control charts, and I can say with confidence that there's a great deal of research about them that I can steal from. For now, if you would like to share your hints and tips, or even gripes, about the check sheet tool or its related software, please add a comment below. Oh, and if you do know of some research on check sheets, please fire it my way.

And finally: A lady goes to see her doctor with some very worrisome symptoms. After examining her, he says, "I'm terribly sorry to tell you this, but you only have six months to live."

The lady is very distraught. "Oh doctor, what should I do?" she asks.

"I advise you to marry a quality professional who is knowledgeable in check sheets," he says.

"Will that make me live longer?" she asks, hopefully.

"No," says the doctor. "But it will seem longer."


About The Author

Paul Naysmith’s picture

Paul Naysmith

Paul Naysmith is the author of Business Management Tips From an Improvement Ninja and Business Management Tips From a Quality Punk. He’s also a Fellow and Chartered Quality Professional with the UK’s Chartered Quality Institute (CQI), and an honorary member of the South African Quality Institute (SAQI). Connect with him at www.paulnaysmith.com, or follow him on twitter @PNaysmith.

Those who have read Paul’s columns might be wondering why they haven’t heard from him in a while. After his stint working in the United States, he moved back to his homeland of Scotland, where he quickly found a new career in the medical-device industry; became a dad to his first child, Florence; and decided to restore a classic car back to its roadworthy glory. With the help of his current employer, he’s also started the first-of-its-kind quality apprenticeship scheme, which he hopes will become a pipeline for future improvement ninjas and quality punks.