The Quality Triangle and Reliability

Fred Schenkelberg
Feb 26, 2018 · 3 min read

The Quality Triangle and Reliability

The quality triangle is an admission that every project has design constraints. Note that reliability is rarely listed directly within the triangle, yet reliability does impact each element of the triad.

In a world where the design team is beset with numerous design for X priorities, understanding how reliability related to the top three and most common set of constraints is imperative.

For any set of priorities, you should be able to convey how addressing reliability performance in the design and assembly process impacts those priorities. Addressing reliability can improve quality, reduce the risk of launch delays, and reduce the cost of a product. All this and improve customer satisfaction as well.

Let’s explore a few ways you can connect reliability priorities to the common quality triangle priorities.

Reliability and Quality

Where you consider reliability as quality over time or that reliability is just one facet of quality, they are intertwined. The perception of quality may take on many elements, such as the industrial design, the color, texture, speed, performance, and may include aspects of wear and durability.

The impact of out of box failures could be classified as a quality or reliability issue. I call it a reliability issue as it costs money in the form of warranty expenses and lost future sales. Avoiding or minimizing field failures allows the other features of a product’s design to satisfy customer’s needs. A failure to start, or function as intended, is a reliability issue and thwarts customer needs satisfying.

Reliability and Time (Deadlines)

A common pushback for reliability plans is, ’it will take too long and delay the program launch’, thus not supported. FMEA’s and HALT both take little time and yield insights on high priority items to address to improve reliability performance. ALT is some cases provide vital information and may take months to get results.

In both cases, as with many other reliability methods, conducting these activities earlier than later permits then to actually reduce the chance of a late in the program discovery of a launch delaying reliability issue. Relying on late in the development cycle prototype testing is nearly always a great way to discover problems that require redesign and program delays (or the issues are ignored and re-discovered by customers as a much high cost).

Front loading reliability work in the product development lifecycle improves reliability performance and reduces the risk of program delays.

Reliability and Cost

Reliability activities take time, resources, and cost money to accomplish. The investment in the development process is often budget constrained. Furthermore, the cost of each product, the bill of material costs is another common cost constraint. Keeping per unit costs down to permit a lower price point for sales, and/or improves the profit margin per unit sold.

Investing in reliability work may require expensive prototype testing or the use of more costly components to improve robustness. Both run counter to the desire to control costs.

Expand the discussion to include total lifecycle costs, and now these investments are prudent. It is which costs we focus on that matters. I suggest as many others do that the total life-cycle costs are what really matters.

Remember that field failures cost customers money under the warranty or lost sales cost us money. These are not always easy to measure or forecast, yet the necessary to make informed decisions concerning adding expense to a product during development.

Understanding the value of reliability investments will help you support the cost constraints while investing in improving reliability performance.


The quality triangle is a tool to assist the shepherding of development process toward product launch. While reliability is not named directly, reliability engineering activities impact each element of the priority triad.

Understanding the team’s priorities and how reliability engineering can support each priority will help ensure your team invests the proper amount of effort into achieving reliability objectives.

Above are just a few ways reliability connects and supports priorities of quality, time, and cost. What other connections do you know about? Leave a comment to describe how you achieve reliability objectives given the set of priorities for the development process.

Originally published at Accendo Reliability.

Fred Schenkelberg

Written by

Reliability Engineering and Management Consultant focused on improving product reliability and increasing equipment availability.

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