In discussions about the Six Sigma methodology, you will often find the equation Y=F(x). It is an important formula in working with the methodology and can serve as a very helpful tool in project management.

When working with the Y=f(x) formula, X stands for the various inputs utilized to generate an outcome, while f represents the process that uses the Xs in pursuit of the desired outcome.

So then, what is Y?

Overview: What is Y?

In Lean Six Sigma, Y represents your dependent output variable. It can also be described as the representation of the outcome of your process. Y is known as the dependent variable as it is dependent on the Xs (inputs). X, in turn, is known as the independent variable as it is independent of Y.

Benefits and drawbacks of Y

There are some key benefits and drawbacks to Y that should be noted:

1. Benefit: Cannot be manipulated

With Y being the dependent variable, it cannot be manipulated by external factors or by the researcher. It is also, therefore, not susceptible to bias.

2. Drawback: Can take a lot of research and time

Dependent variables are established from a great deal of research and a comparatively long amount of time, while an x can come from nearly anything.

3. Benefit: Predefined formula

One advantage of Y over X is that Y is generally determined from a predefined formula.

Why is Y important to understand?

Y is important to understand for the following reasons:

1. Relationship to various inputs

It is important to understand Y so that you can have a solid grasp of the relationship between how various Xs (inputs) can affect your output (Y).

2. What Y symbolizes

Understanding Y is important in that it symbolizes the effects or symptoms of problems.

3. Six Sigma

The Y=f(x) formula is a cornerstone of the principles of Six Sigma, so it is important to understand all the components of the formula.

4. Predictive modeling

Having an understanding of Y allows you to be more effective with predictive modeling.

An industry example of Y

A crowdsourcing campaign is underway for the soft launch of a new invention into the marketplace. The funds raised for this campaign will allow for an initial product run that encompasses the initial production of the new invention, marketing, and lining up with a proper distributor.

The campaign manager is trying to decide how many tiers of prizes should be offered to contributors. Looking at various other similar campaigns as an example, the manager is able to create a solid model to explore. In this situation, X represents the number of tiers there are for prizes, while f stands for the number of people that have gone to the company website and interacted with it for more than 30 minutes. Y represents the number of donations. The campaign manager is able to determine that with a large number of tiered gifts that can cover every price point, the company is likely going to receive more donations.

3 best practices when thinking about Y

There are some key practices that you should think about when it comes to Y in Six Sigma:

1. Determine your Y to help with DMAIC

When using the Six Sigma DMAIC stage, you will first want to define what Y is. This will be the specifically defined problem in a process.

2. Find the Xs that have the largest impact

During the measurement phase of DMAIC, you will want to trim down your Xs to just the ones that have the largest impact on your Y.

3. Your final checkpoint

When working with a process management chart, think of Y as the final check that concludes your process cycle.

Frequently Asked Questions (FAQ) about Y

What are some other terms for Y?

You can call Y either the dependent variable or the predicted variable.

What kind of relationship do X and Y have?

X and Y are generally thought of as having a cause-and-effect relationship.

How can you be sure of the relationship between an X and a Y?

This is done through verification and quantification using various graphical and statistical tools.

Know your Y

With Y=f(x) being such a major part of the Six Sigma methodology, it is important for you to be able to determine what your Y is in order to conclude your data. Understanding Y helps you run a successful project and find the best solutions for your organization.
About the Author

Lori Kinney