The 5 most used Quality Management tools in engineering – 2023 Edition



If you have ever wondered about the best quality management tools, worry not; I’ve got you covered.

This post will present the five most used quality management tools in engineering. We will be reviewing its uses and how we can make the most out of them.

What are the most used quality management tools in engineering?

  1. Checklists
  2. Pareto Charts
  3. Cause and effect diagram (Ishikawa diagram)
  4. Scatter diagram
  5. Process flows

We will be breaking down each quality management tool into:

  • What is it?
  • How is it used?
  • Why is it important and relevant?

This way, we will be able to see how to implement them in our business and clearly understand what the examples mean.


What is a checklist?

A checklist is a sequence of tasks or things presented in a way that makes it easy for the user to accomplish something.

If you have ever gone for groceries, chances are you have used a list to ensure you buy everything you need and prevent you from going again to pick up something you missed.

Checklists are one of the essential tools used not only in engineering but in almost any aspect of our lives in which we want to organize ourselves.

Checklists can be sequenced or not, and there are many uses for them. 

How to use a checklist in engineering?

The first step is to define what we will use the checklist for clearly. 

If we need a sequenced checklist (task A happens before B, B before C, etc.), the first step is to map out all the steps required and the order they need to happen.

The mapping exercise will provide the foundation for the checklist. If this is the first time looking at giving structure to a step, it’s essential to involve all stakeholders to ensure no steps are missing.

If it’s not a sequenced list, the task becomes more manageable as all we need to do is ensure we record everything that needs to happen.

Have a look at the two pictures below. They are both checklists; one is sequential, and the other isn’t.

fitting an engine checksheet
materials required to fit an engine

Why are checklists essential as quality management tools in engineering?

All of us are human, and humans make mistakes, even the best ones.

Checklists are inexpensive compared to potential quality issues that could damage your reputation and prevent you from getting future clients.

Checklists are your ally if you want to ensure a task gets done right the first time.

Standardization is what makes checklists so powerful. They ensure quality and reduce downtimes and allow you to put your effort into what matters most, reducing decision fatigue.

Last but not least, you could use them as your benchmark in your continuous improvement cycle. If you or your team see gaps in its structure after a few days or months of using the same checklist, you can update it to save even more time or prevent any unforeseen quality issues.

Pareto charts

What is a Pareto chart?

A Pareto chart is a double chart that contains:

  • An ordered bar chart (number of times a specific event occurs plotted as a bar) in descendant order.
  • A line represents the cumulative total of the different elements in the bar chart.

Pareto charts take their name from Vilfredo Pareto, an Italian economist, and civil engineer.

He made outstanding contributions to studying income disparities among classes and the analysis of people’s choices.

The Pareto principle takes its name from him, stating that 80% of the consequences come from 20% of the causes.

The previous statement is tremendously powerful, as we will see in the section below.

How to use Pareto charts in engineering?

Imagine we ask our customer service team to log every time a customer makes a complaint.

We investigate those complaints and give them a root cause, so now we have a table of complaints and root causes.

The root causes can contribute tremendously to our continuous improvement cycle. Let’s plot those root causes in a Pareto chart as shown below.

If we follow what we said above, 80% of our issues come from 20% of the causes. 

That means we can eliminate 80% of our problems if we focus on the top 20% of causes. We can determine the 20% by following the cumulative percentage shown in the bar.

Amazing, don’t you think?

Why are Pareto charts necessary in engineering?

Pareto charts are not only crucial in engineering. They are standard practice in almost every industry.

From a cost point of view, they are one of the most cost-effective ways of prioritizing your efforts to improve your business. 

As I have mentioned before, if focusing on only 20% of your causes, you can get rid of 80% of your issues. It looks like a no-brainer in terms of impact and efficiency.

Cause and effect diagrams

What are cause and effect diagrams, also known as fishbone diagrams?

Cause and effect diagrams are one of the main tools in any engineer’s toolbox. Kaoru Ishikawa, a professor in engineering from the University of Tokyo, created them.

A cause and effect diagram helps you determine the cause of an event by evaluating different elements of your product or service. It simplifies evaluating risks and standardizes the process.

How to use a cause and effect diagram in engineering?

The structure is quite simple. Let’s have a look at the example below.

cause and effect original diagram

We need to put the event as the “head” of the fish. We then have the different branches. There are six standard branches in manufacturing, as shown in the picture.

  • Measure: How do we quantify the event?
  • Man: What interactions does the human have with the event?
  • Method: Is there anything wrong with the process?
  • Environment: Are there any external conditions influencing the event?
  • Material: Are the materials contributing to the event?
  • Machine: Are the tools contributing to the event?

These are some of the questions we can ask when going through the cause and effect analysis.

Let’s have a look at a direct example in engineering.

car will not start cause and effect diagram

The previous example highlights a widespread fault, a car not starting.

Different things could contribute to that issue. As you can see, I have highlighted one specific topic relevant to each area.

In most cases, you will realize that filling every single category is not necessary to reach the primary root cause.

Why are cause and effect diagrams important as quality management tools in engineering?

When evaluating an issue or a potential event, it’s crucial to have a consistent approach to resolving it.

I will be blue in my face by the end of this article, but systematization is one of the most powerful things you can introduce to ensure quality.

Having a systematic approach to evaluating causes and effects will give you more and better insights into what might go wrong.

The best bit about it is that you can involve your team and run a brainstorming session on whichever topics worry you to maximize the impact and power of the tool.

Scatter diagrams

What is a scatter diagram?

A scatter diagram is a chart that allows you to understand the relationship between 2 variables.

These two variables can be whatever you can imagine. For example, on one axis, we can plot the height of secondary school students and, on the other, their weight.

It can give us an indication of whether the two variables are correlated.

How to use a scatter plot in engineering as a quality management tool?

Ideally, you want to use something like Microsoft Excel to help you out with this task.

Or you can be like me and code something in Python with Plotly to make it look fancy. Either way, you need to use something that allows you to plot the values.

Let’s have a look at the chart below.

As you can see, on one axis, I have horsepower, and on the other, I have weight.

This cloud of points gives us some insights into the data we are exploring. In general terms, the heavier a car is, the more horsepower it requires to move.

Common sense tells me this is a logical relationship. If a car needs to achieve 60 MPH, the heavier it is, the more power it requires.

Why are scatter plots important?

As I have mentioned before, scatter plots can help you understand if there is a correlation between the variables you are studying.

If the variables are correlated, you could go deeper in your study to understand if one causes the other or vice-versa. 

It was easy to see the trend rising as the cars got heavier in the previous example. There are many other questions we can ask after exploring the data, for example:

  • Will heavier cars consume more fuel?
  • Is weight the only factor in determining horsepower?
  • Can we reduce weight and maintain horsepower?

Correlation doesn’t mean causation, and that’s super important to understand.

Scatter plots could help you understand your data in a way you haven’t thought of previously. Use them wisely.


What are flowcharts?

Flowcharts describe all the steps required to achieve a goal or complete a task.

Hang on a minute. Is that not the same as a Checklist?

Not necessarily. Checklists, when used correctly, define all the small steps to complete a task very accurately.

Process flows are top-level views that allow you to achieve a goal.

Think about the following example in engineering. 

building a car flowchart

The process flow shows a very top-level car creation process. I would use the checklist to specify a unique point of this process.

How to use a flowchart in engineering as a quality management tool?

If you already have a process in place, it’s a matter of documenting and investigating if any gaps need covering.

If not, the first step is to understand the end goal and our starting point.

After that, we need to lay the different blocks that will allow us to get to the end goal from our starting point.

Make sure your team contributes to this exercise, especially those in charge of executing the different blocks of work.

In engineering, we need many different functions to contribute to our processes. Get the main stakeholders together in a room to get your flowcharts ready.

Those are your key members. Make sure they understand why it is vital to use flowcharts if they want to ensure quality.

Why are flowcharts necessary?

Flowcharts allow you to represent what’s required to achieve a specific goal.

When used correctly, they prevent issues from happening. They also allow you to step back and see if there are any gaps in your processes.

They are tremendously helpful training tools too. If you have a new person joining the team, the combination of process flows and checklists could reduce the time you need to train that person.

When combining different flowcharts, you could end up with a QMS, which is a great way to ensure quality.


In this article, I have presented five different quality management tools used in engineering.

The key takeaway is: 

We must standardize our actions and tasks and use data to make conscious decisions and improvements to ensure quality.

To standardize our actions and tasks, we can:

  • Use checklists to ensure we don’t forget any steps to achieve a goal.
  • Use cause and effect diagrams to understand the root of our issues and resolve them.
  • Use flowcharts to detach ourselves from the small details and have a clear overview of the whole operation.

To make conscious improvements through data, we can:

  • Use scatter diagrams, to understand the relationship between different variables.
  • Use Pareto charts to maximize the impact of our continuous improvement efforts.

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