Friday, February 28, 2014

Lean Quote: Quality Controls Requires Effective Tools

On Fridays I will post a Lean related Quote. Throughout our lifetimes many people touch our lives and leave us with words of wisdom. These can both be a source of new learning and also a point to pause and reflect upon lessons we have learned. Within Lean active learning is an important aspect on this journey because without learning we can not improve.

"Quality control is more than just a state of mind. It requires effective tools.— McCormack

Most organizations use quality tools for various purposes related to controlling and assuring quality. Although there are a good number of quality tools specific to certain domains, fields, and practices, some of the quality tools can be used across such domains. These quality tools are quite generic and can be applied to any condition.

The Seven Basic Tools of Quality is a designation given to a fixed set of graphical techniques identified as being most helpful in troubleshooting issues related to quality. They are called basic because they are suitable for people with little formal training in statistics and because they can be used to solve the vast majority of quality-related issues.

The tools are:

  1. Check Sheets – A generic Tool which can be used for collection and analysis of data. A structured and prepared form that can be adapted for wide variety of issues
  2. Control Charts – This is a graphical technique,which can be used to study the changes to a process over time
  3. Pareto Chart – This is another graphical technique, which can be used to identify the significance of individual factors
  4. Scatter Chart – This is used to identify the relation between variables, by plotting pairs of numerical data, with one variable on each axis. The points will be falling on a line or a curve, if the variables are related.
  5. Cause and Effect Diagram (Also called as Ishikawa Diagram or Fishbone Diagram) – This can be used to structure the brain Storming Sessions. It is used to sort ideas into useful categories. Many Possible Causes are identified for a stated problem and the effect on the problem are identified
  6. Flow Chart (Stratification Charts) - This tool is used to identify the patterns within the data collected from multiple sources and clubbed together. It is used to identify the meaning of the vast data by identifying patterns.
  7. Histogram – It looks very much like a bar chart. it is used to identify the frequency of occurrence of a variable in a set of data.

The seven basic tools of quality can be used singularly or in tandem to investigate a process and identify areas for improvement, although they do not all necessarily need to be used. If a process is simple enough – or the solution obvious enough – any one may be all that is needed for improvement. They provide a means for doing so based on facts, not just personal knowledge, which of course can be tainted or inaccurate. Ishikawa advocated teaching these seven basic tools to every member of a company as a means to making quality endemic throughout the organization.

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  1. In my experience, using control charts still takes statistical analysis to find Upper and Lower control limits. Would a quality expert still need to find these limits and then provide the chart to employee's, who can then plot data as it comes available in the process?

    1. Plotting the data in real time provides some indication of variation. Control limits are calculated based actual data. You can set this up manually or by software, The important thing is to select key processes, collect data, analyze data, and provide feedback to operations and process owners regarding said process performance. This isn't always the best tool for all key processes.