Six Sigma tools to know — DPU, DPMO, PPM, and RTY

Learn about the Six Sigma tools

If you’re looking to implement the Six Sigma approach to your company’s production, you may want to know more about some of its powerful tools and techniques for eliminating defects and improving efficiency.

After you’re done reading this blog post, you will be more familiar with these four Six Sigma tools — defects per unit (DPU), defects per million opportunities (DPMO), parts per million defective (PPM), and rolled throughput yield (RTY). You’ll know how they work and how to calculate each using your company’s data.

In this article, you’ll learn about:

Key concepts to know

Before diving into the four different Six Sigma tools included in this blog post, let’s understand these terms used in the Six Sigma framework:

Defects per unit (DPU)

The DPU is a metric that estimates the mean count of defects for every completed unit. To deduce the DPU, one must divide the total number of defects identified within a sample by the total number of units within that sample.

The formula to calculate the DPU is the following:

Defects per unit formula

As an example, if you have 10 defects within a lot of 100 toys, then the DPU comes out to be 0.1.

Defects per million opportunities (DMPO)

DPMO is a crucial tool within Six Sigma, as it defines the proportion of defects in 1 million opportunities.

It essentially illustrates how often a fault or error occurs relative to every possible opportunity for a fault to arise.

The formula to calculate the DPMO is the following:

Defects per million opportunities formula

For instance, if a process yields 10 defects amidst 2,000 opportunities, the resulting DPMO will stand at 5,000.

Parts per million defective (PPM)

PPM, another significant part of Six Sigma, signifies the number of unsellable, defective units within one million units.

The formula to calculate the PPM is the following:

Parts per million defective formula

For example, if a batch of 200,000 units has 400 that are deemed defective, the PPM would be calculated as 2,000.

Rolled throughput yield (RTY)

Known alternatively as the first-pass yield, RTY is the likelihood or frequency at which a process delivers a unit devoid of defects. This requires an intricate process map to enumerate the steps involved in the process.

The formula to calculate the PPM is the following:

Rolled throughput yield formula

The reliability formula for a system in series with n process steps is: Rs = (R1) (R2) (R3) (R4) … (Rn)

The formula can also be reworded as follows — as the dependability of a process step mirrors the yield of that specific step when the performance metric is quality, the equation consequently becomes:

Rolled throughput yield formula

To grasp this concept better, you can think of a hypothetical case. If the yields at the three respective process stages are 0.9, 0.8, and 0.95, the resulting RTY is 0.684, or 68.4%.

Use powerful software to calculate and track these Six Sigma tools

Now that you’ve learned more about these four Six Sigma tools, you know that they can enable you to understand the current state of your manufacturing or service process and assess the efficacy of any changes you implement.

When you’re ready to get started, you may want to evaluate whether your current software can incorporate these Six Sigma tools. Adobe Workfront can make this process easier for you.

Workfront can empower you and your teams, making it easier to launch campaigns and deliver to your customers personalized experiences at scale.

If you want to level your process management and improve your strategies, take the leap toward operational excellence with these four Six Sigma tools and with the aid of Adobe Workfront by taking a product tour or watching an overview video.