# Taguchi Method of Quality Control: Definition, Example, and Uses

![Young woman, in factory, inspecting conveyor belt](https://www.investopedia.com/thmb/3wU0EWoCmfWMHxuxmyMmhvgSFgc=/1500x0/filters:no_upscale():max_bytes(150000):strip_icc()/young-woman--in-factory--inspecting-conveyor-belt-961181850-d82276e0629a404e85fd02777333b7ef.jpg)

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> **Definition**
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> The Taguchi Method of quality control emphasizes solid design and product process to achieve consistency and high quality, minimizing uncontrollable variations.

## What Is the Taguchi Method of Quality Control?

The Taguchi method of quality control is an engineering approach that emphasizes the roles of [research and development](https://www.investopedia.com/terms/r/randd.asp) (R&D), and product design and development in reducing the occurrence of defects and failures in manufactured goods.

This method, developed by Japanese engineer and statistician Genichi Taguchi, considers design to be more important than the manufacturing process in [quality control](https://www.investopedia.com/terms/q/quality-control.asp) and aims to eliminate variances in production before they can occur.

### Key Takeaways

*   The Taguchi method is a quality control approach in engineering that emphasizes product design and development to ensure efficiency, consistency, and reliability.
*   Developed by Genichi Taguchi, the method prioritizes robust design over reactive quality checks during manufacturing, aiming to prevent variation at the source.
*   Taguchi’s philosophy stresses that improving quality during the design phase has a greater impact than trying to correct defects later in production.
*   This proactive method has been successfully implemented by major global companies including Toyota, Ford, Boeing, and Xerox to enhance product performance and reduce manufacturing costs.

## Understanding the Taguchi Method of Quality Control

The Taguchi method gauges quality as a calculation of loss to society associated with a product. In particular, loss in a product is defined by variations and deviations in its function as well as detrimental side effects that result from the product.

Loss from [variation in function](https://www.investopedia.com/terms/a/acceptance-testing.asp) is a comparison of how much each unit of the product differs in the way it operates. The greater that variance, the more significant the loss in function and quality. This could be represented as a monetary figure denoting how usage has been impacted by defects in the product.

## Example of the Taguchi Method of Quality Control

If the product is a precision drill that must consistently drill holes of an exact size in all materials it is used on, then part of its quality is determined by how much the units of the product differ from those standards. With the Taguchi method of quality control, the focus is to use research and design to ensure that every unit of the product will closely match those design specifications and perform exactly as designed.

Loss from detrimental side effects on society speaks to whether or not the design of the product could inherently lead to an adverse impact. For example, if operating the precision drill could cause injury to the operator because of how it is designed, there is a loss of quality in the product. Under the Taguchi method, work done during the design stage of creation would aim to minimize the possibility that the drill is crafted in a way that could cause injuries to the operator.

From a higher perspective, the Taguchi method would also strive to reduce the cost to society to use the product, such as by designing goods to be more [efficient](https://www.investopedia.com/terms/e/efficiency.asp) in their operation rather than generate waste. For instance, the drill could be designed to minimize the need for regular maintenance. 

## History of the Taguchi Method of Quality Control

Genichi Taguchi, a Japanese engineer and statistician, began formulating the Taguchi method while developing a telephone-switching system for Electrical Communication Laboratory, a Japanese company, in the 1950s. Using statistics, he aimed to improve the quality of manufactured goods.

By the 1980s, Taguchi's ideas began gaining prominence in the Western world, leading him to become well-known in the United States, having already enjoyed success in his native Japan.  

> **Fast Fact**
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> Big-name global companies such as Toyota Motor Corp., Ford Motor Co., Boeing Co., and Xerox Holdings Corp. have adopted his methods.

## Signal-to-Noise Ratio and Robust Design

A central concept in the Taguchi method is the [signal-to-noise](https://www.investopedia.com/terms/n/noise.asp) (S/N) ratio. This quantifies how much desired performance (the "signal") stands out from variability or noise. In quality engineering, a higher S/N ratio indicates a product or process that consistently performs close to its intended target

Taguchi categorized different types of S/N ratios depending on the desired outcome. For example, users could read metrics such as "larger-the-better," "smaller-the-better," or "nominal-the-best" based on the nature of the [performance metric](https://www.investopedia.com/terms/m/metrics.asp).

Closely tied to this is the concept of robust design, which aims to make products that are not only high-performing but also consistently reliable. Rather than trying to eliminate all sources of variation, robust design accepts that noise factors such as environmental changes, wear and tear, or user handling are inevitable. The goal is to engineer a product or process that is minimally affected by those uncontrollable variations.

## Criticism of the Taguchi Method of Quality Control

One of the primary concerns is that it simplifies the statistical analysis of complex systems. Critics argue that Taguchi's use of certain arrays and ratios may obscure deeper interactions between variables. For this reason, some people may prefer more rigorous methods like [ANOVA](https://www.investopedia.com/terms/a/anova.asp) or [regression analysis](https://www.investopedia.com/articles/financial-theory/09/regression-analysis-basics-business.asp).

Another criticism is that the Taguchi method assumes that interactions between variables are either minimal or irrelevant. This won't always be the case in real-world applications. Complex manufacturing and design processes often involve intricate interdependencies that Taguchi’s factorial designs might overlook.

Finally, some practitioners find the Taguchi method to be difficult to integrate into modern quality management systems. Its terminology, assumptions, and statistical techniques are not always intuitive. As a result, adoption and implementation can require substantial training or adaptation.

## What Is the Taguchi Method of Quality Control?

The Taguchi method is an engineering-based quality control approach that emphasizes improving product design and development to reduce defects and ensure consistent performance across all manufactured units.

## Who Developed the Taguchi Method?

Japanese engineer and statistician Genichi Taguchi developed the method in the 1950s to improve product quality using statistical techniques, particularly by addressing variability during the design phase rather than in manufacturing.

## How Does the Taguchi Method Differ From Traditional Quality Control?

Traditional quality control often focuses on detecting and correcting defects during manufacturing. In contrast, the Taguchi method focuses on preventing variation by optimizing product and process design from the outset.

## How Does the Taguchi Method Define Quality Loss?

Taguchi defines quality loss as the cost to society caused by deviation from a product’s ideal performance. This includes reduced functionality, customer dissatisfaction, and negative side effects such as safety hazards or waste.

## The Bottom Line

The Taguchi method of quality control is a design-focused engineering approach developed by Genichi Taguchi. It aims to reduce defects and variability by improving product design before manufacturing begins. It emphasizes the use of statistical tools to create robust products that perform consistently under various conditions, thereby minimizing societal loss from poor quality. 

> **Article Sources**
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> 1.  American Society for Quality. "[Genichi Taguchi](https://asq.org/about-asq/honorary-members/taguchi)."
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> 2.  American Society for Quality. "[Genichi Taguchi](https://asq.org/about-asq/honorary-members/taguchi)."
>     
> 3.  Automotive Hall of Fame. "[Genichi Taguchi: Hall of Fame Inductee 1997](https://www.automotivehalloffame.org/honoree/genichi-taguchi/)."