In business, it is necessary to have a solid understanding of what, exactly, is going into your processes. After all, if you do not know your inputs, how can you expect to be able to keep your output outcome desirable, repeatable, and consistent?

Your X’s play a massive role in the outcomes you achieve. In Six Sigma, X’s are not just part of a math problem that may or may not have a bearing on real-world concerns. Instead, X’s are an integral part of making sure you are optimizing the full potential of your operations.

Overview: What is X?

In algebraic equations, x is generally meant to signify an unknown variable or quantity. It can also be used as an independent variable, while Y is a dependent variable. This means that Y (the outcome) is dependent on X (the inputs). In Six Sigma, X refers to an independent input that can be a contributing factor in the output (Y) of a particular process.

1 benefit of X and 2 drawbacks

There is definitely a benefit to X, but there are also some clear drawbacks that should be considered:

Benefit 1: It can help determine a favorable outcome

Having the right X’s (inputs) typically have a major factor in determining achieving the desired output (Y).

Drawback 1: Process variation

X’s are responsible for variation in a process. Too many X’s can contribute to the potential for too much variation in a process, which can lead to disruption in operations. It can also have a negative impact on the supply chain and interfere with operations functioning at an optimal level.

Drawback 2: Can cause a negative outcome

Since your output is so dependent on having the right inputs (or X’s), having the wrong X’s can lead to an undesirable outcome.

Why is X important to understand?

X is important to understand for the following reasons:

Better for your business

Understanding X’s (inputs) and Y’s (outputs) gives you the ability to define ideal outcomes for your business and what actions it will take to achieve them.

Evaluation of your processes

By having a solid understanding of your X’s (inputs), you can evaluate them in the implementation of new processes or operations as well as analyze your current ones.

Deconstructing a large goal

Possessing knowledge of X’s (inputs) is important in an organization because it allows for the deconstruction of a large goal and identifies the factors that could contribute to the success of your project.

An industry example of X

In a manufacturing plant, productivity has been beginning to slow. In order to determine why, a process map is created to determine what the root cause could be for the slower productivity. A team is put together to analyze the plant’s entire manufacturing process, top-to-bottom. The team leader assigns each member of the team to list all of the X’s (inputs) that they can think of that could have a bearing on the plant’s output (Y).

3 best practices when thinking about X

Here are some best practices for when you are thinking about X in relation to your processes:

1. For process maps

When creating a process map, try not to use more than 12 steps in your process to determine your process inputs.

2. Be aware if your X’s are controlled or uncontrolled

When analyzing your X’s and their effects on your Y’s, be aware of whether the input is controlled or uncontrolled. A controlled input means you can adjust it during your process. An uncontrollable input means that you cannot control it or may be unwilling to control it due to factors like cost or company culture.

3. Have help identifying all of the potential X’s

Have a project team involved in finding all the X’s (inputs) that could have an effect on your Y’s (outputs). There is strength in numbers, so having others identify other potential X’s may lead to you finding inputs that you might not consider on your own.

Frequently Asked Questions (FAQ) about X

What does X represent in a process map?

In a process map, X is a process parameter. This means that it is a process variable in that it is an input of the process step that can have bearing on the result.

What is an X-Y matrix?

An X-Y matrix is also known as a cause-and-effect matrix. It is utilized to determine the most relevant causes in relation to effects. It is used to describe the relationship between process inputs (X’s) and process outputs (Y’s). It can be a particularly useful tool for root-cause analysis.

Where do X’s figure into DMAIC?

X’s come into play during the Analyze stage of DMAIC, where uncovering root causes are important.

Have the right X’s to achieve favorable Y’s

It should be clear that whatever you put in can have an effect on what you end up with. Having a clear understanding of the inputs that make up your process will go a long way toward helping you achieve the results your organization is looking to achieve.
About the Author

Lori Kinney