Tally Chart:: Continuous Process Improvement
Continual Process Improvement
How can a tally chart or check sheet help with continual process improvement? Well as W.E. Deming supposedly once said “In god we trust, All others bring data”, the meaning being that if we really want to know what is going on we had best get off of our seats and go get some hard facts and figures using tools such as tally charts for continuous process improvement. One of the simplest tools for doing so is the simple tally sheet, something that most of us will be familiar with from school let alone in business! This tool is far too often forgotten but it’s power to collect data quickly simply and efficiently should not be overlooked.
Almost everybody knows how to use a check sheet and it is so simple that even the least skilled employee should have little trouble using it.
Tally Chart for Continuous Process Improvement
What is a Tally Chart
A tally chart is probably the simplest and oldest way to record data, it is merely a table of how often a specific occurrence happens, normally put together when the event occurs.
I am sure that as a child you may have sat beside the road with your teacher with a tally chart and put a mark to show every time a red, blue, silver or white car went past you, I am not sure if in these days of health and safety if these trips still occur. But I know that you will have use a tally chart within your school career.
It’s use in business is as simple as this, it can be used to record defects against categories as a machine works, the number of requests made of a department each hour and so on. As one of the basic quality tools a tally chart feeds into many of the other tools to help you achieve continuous process improvement. Its strength as a simple method to gather data is unrivaled.
Tally Chart Example
Creating a Tally Chart
A tally chart should be as simple to use as possible, you should not have more than around 10 categories against which to make your tally mark, more than this and you run the risk of mistakes and wasting time trying to find the correct box to tick, I have seen far to many data collection sheets on factory floors with 30 or 40 reject causes and sub causes that the operator has to decipher, usually resulting in “other” being the main cause of rejects as the operator cannot be bothered to find the right box.
You can use pareto analysis to identify the top categories for your tally chart to use, this is a very simple tool to identify the vital few areas the cause the majority of the problems.
Collect Relevant Data on your Tally Chart.
When using a tally chart ensure that you use relevant data and that the people recording the data understand what you are looking for.
An example is a bottling plant that I once visited and did some work for as a consultant, they collected reams of data on the shop floor and their tally charts showed that over 90% of their downtime and rejects were caused by incorrect bottles. They identified the causes as being bottles that were of the wrong shapes and dimensions, thousands were rejected every day!
The result of this was a very sour relationship between the supplier and the company, a lot of time being spent on investigating the dimensions of the bottles. Re-dimensioning of drawings as people could interpret them in different ways. Even the commissioning of new tools to try to alleviate the problems.
But was this data correct? Were the operators recording what the engineers and management actually wanted them to record and did those engineers and managers themselves understand what they were looking for?
The answer of course is no, instead of recording what actually went wrong on the line, such as a bottle falling over and causing line jams or a cap not being fitted the operators assumed that the problem was down to an incorrect bottle and recorded what they incorrectly believed to be the root cause.
One day spent on the line collecting the real issues not supposed causes gave some real data that could be looked at, combined with actually observing the process with a critical eye resulted in all of these problems vanishing within 48 hours and the “reject” bottles all being able to be processed on the line! Not one bottle that had been rejected failed to run through the line.
Years of arguing and and expense were caused by not recording relevant data and people failing to understand and question the data! It is important to ensure that you record actual data and don't make assumptions.
Tally Chart Video
Data Analysis from your Tally Chart
Analysis itself is relatively simple, you can analyze your data by using a simple histogram (Bar Chart). Displaying the data as a visual chart (in Pareto order) is far more effective than just a table of numbers.
A bar chart arranged as a Pareto with the most frequent occurrence first going down to the least will allow you to quickly see exactly what is going on. For instance for the case study mentioned above most of the problems were for bottles falling over. This was because the guides on the bottling line were incorrectly set, in fact most were actually upside down. This was quickly evident when we pulled the design drawings to have a look.
Other issues such as the cap not fitting required the use of a small brainstorming session to come up with potential reasons followed by some careful observation and additional data gathering. The tool had multiple locations to hold the bottle in place for the cap to be applied, one location was out of position. Correcting it solved the problem.
These two problems made up over 80% of the problems on the line and were solved in less than 24 hours.
Check Sheet Video
Resolving the Problems highlighted by your Tally Chart
The data from your tally chart once organized as a histogram (bar chart) or a Pareto chart can then be used to direct your efforts to resolve problems and improve your business performance. After all what we are aiming for here is continuous process improvement, not just gathering data. Now we need to find a solution to the top issues as indicated within your analysis.
Techniques such as Brainstorming, Fishbone Analysis and the 5 whys are all powerful tools that can help you focus on the issues highlighted by your data collection. Starting with the highest problem on your analysis you can work your way through the causes continually improving your processes.
Continuous process improvement using quality tools
Continuous Process Improvement
Your tally chart or check sheet is often the starting point for any data gathering and analysis. Used with many of the other quality tools mentioned above your check sheets can help to drive improvement.
These tools are the simplest to use and undersand and can be used by any team of operators to improve their own processes. It is very important to train all of your operators in the use of quality tools such as this to ensure that your problems are banished for good.
You can learn about the other quality tools by reading; the 7 quality tools.