What Is Quality Control? A Complete Guide

By Indeed Editorial Team

Updated 22 September 2022

Published 6 July 2021

The Indeed Editorial Team comprises a diverse and talented team of writers, researchers and subject matter experts equipped with Indeed's data and insights to deliver useful tips to help guide your career journey.

Quality control is essential for any company that manufactures products or provides a service. It helps improve customer satisfaction by consistently delivering quality products or services, reduce wastage of resources and increase efficiency and profits for the company. Because certain industries rely on quality control to set product standards, employers may ask you about this part of the job during interviews. In this article, we would discuss what is quality control, why it is important and what the 4 types of quality control are.

What Is Quality Control?

What is quality control or QC, can be explained as the process that businesses use to ensure that a product or service adheres to a pre-defined set of quality standards and meets the requirements of customers or clients. Quality control usually requires the business to create an environment where employees and management are always striving for perfection. This requires extensive training, creating benchmarks for measuring product or service quality, and testing to check for any significant variations in quality.

Related: What Is Total Quality Management? (A Complete Guide)

Why Is Quality Control Important?

There are numerous reasons to enforce quality control:

  • Promoting quality consciousness: It is essential for all employees who are part of a service or production effort, to be aware of the minimum quality requirements that the brand/product/service has. When all involved employees are conscious of quality parameters at all stages of manufacturing, the brand can consistently deliver the same quality in its products, over time.

  • Lowering operational and production costs: When products do not meet quality standards, they often require to be called back. When customers raise quality issues, they would also expect compensation of some form, like a replacement or refund. All these are additional costs that the company has to bear. Proper quality control can eliminate these additional costs, while also optimising production efforts.

  • Improving customer satisfaction: Customers expect a consistent user experience when they invest money in a product or service. As long as a company/brand can provide a consistent experience, customers remain satisfied and continue to invest money in their products/services. In this way, quality control improves customer satisfaction and even brand loyalty.

  • Improving brand reputation: Brands persevere to create a good reputation in their market. Good quality control ensures that a brand's reputation stays intact at all times. In the age of social media, a single instance of quality compromise can have adverse effects on sales and reputation.

  • Boosting morale in the workplace: Employees who help produce a commodity or deliver a service are required to ideally be proud of what they do. Quality control ensures that employees are conscious of the quality of their company's products/services. This leads to overall improvement of morale in the workplace.

  • Improving methods of production: Quality control enables companies to consistently optimise and streamline their production chain. This results in higher productivity and design improvements.

  • Increasing sales: If your company sells quality products consistently, it can retain its existing customers while steadily attracting new customers. This means that your sales would continue to go up with time.

  • Using resources effectively: Quality control aims to reduce wastage, be it in terms of time, effort or resources. A company practicing quality control would utilise its resources effectively and maintain a degree of efficiency in its operations.

Related: What Is Service Quality? (With Importance And Dimensions)

Quality Control Process

Companies typically follow a set procedure to ensure quality control, including:

Setting testing standards

To implement a quality control program, a company is required to first decide what standards they want to meet. Next, they require to determine the extent of the actions they want to take. For example, the QC team is required to decide how many samples would be taken for testing, how the selection of samples would take place and what exactly the testing procedure would be.

Testing raw materials and various stages

Quality control usually involves testing every step of a company's manufacturing process. QC employees may begin by testing the raw materials that are used to create a product and then testing at various stages within the manufacturing process to identify where any problems are occurring.

Correcting problems

Employees may be required to correct problems to prevent them from happening again in the future. The exact quality control that a company uses is dependent on the industry and product.

For example, in food manufacturing, the company QC team performs microbiological testing to ensure that the completed product does not make consumers sick. They may also perform quality control of the food in its packaging to ensure that it does not perish before a given expiry date. In the car manufacturing industry, its evident that quality control may focus on collision and skid tests.

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Data collection and decisions

After problems are identified, real-world data would be collected and the reports would be delivered to management. Finally, corrective action is required to be taken. For example, the company may decide to repair any remaining defective production units or eliminate them altogether to invest in new technology.

If too many of the products are defective, a company is required to establish a plan for improving the production process. If the problem is with the supplies being used, the company is required to try to purchase better quality raw materials. Finally, the quality control method is required to be ongoing to monitor for new signs of problems.

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What Are The Four Types Of Quality Control?

Companies all over the world use different quality control methods. The 4 prominent types of quality control are:

1. X bar chart

To make an x bar chart, you would be required to randomly select products and note the degree to which each product has varied from an ideal standard, for a given attribute. In an x bar chart, the degree of variance is plotted on the y-axis and the number of samples tested is plotted on the x-axis. By studying the graph of an x bar chart, a company can find out whether defective pieces come out randomly or as a result of systemic errors.

For example, you could test 10 randomly selected products and find that one is defective. On testing 100 randomly selected products, you find that 10 are defective. This indicates that your production system is faulty or inefficient, with a one in ten chance of producing a defective piece.

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2. Six Sigma

The six sigma process is a quality control methodology that assures a success rate of 99.99966% in terms of quality control. Professionals in QC, who practice the six sigma methodology, help companies identify and eliminate defects in their production mechanisms and business processes. There typically would be no room for systemic errors or quality concerns afterwards.

While the six sigma methodology may be helpful for improving the efficiency of existing mechanisms and processes, it rarely leads to innovation or disruption in an industry.

3. 100% inspection mode

The 100% inspection method is labour and time intensive as it requires a company to have each part of every single product examined for quality. This method is usually employed in the QC of luxury goods like super-cars and jewellery. It is more difficult to incorporate in industries that mass-produce a large volume of goods in short periods of time.

Related: What Does A Quality Inspector Do? (With Skills And Salary)

4. Taguchi method

The Taguchi method of QC gives more importance to research, development and design. Its philosophy revolves around the assertion that any potential for variance in a product can be eliminated by making some calculated changes in the design of the product. Here, you are required to think about possible areas of variance or defects and eliminate them at the design stage, so they do not occur at all.

What Is An Example Of Quality Control?

For an example of quality control in practice, let us take the case of a stuffed toy manufacturer, who wants to do quality control on a particular teddy bear product. The company identifies 8 parameters where quality has to be controlled, to ensure that all teddy bears have a consistent look and feel. The QC team (comprised of one or more people, depending on the size of the operation) has to ensure that every teddy bear:

  • Has no choking hazards

  • Weighs exactly 1kg

  • Can be exposed to water, without the colours running off

  • Can be exposed to harsh light, without fading of colours

  • Sits upright when placed on a flat surface

  • Has no undone stitches

  • Has no stains

  • Has erect ears

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Quality Control Vs. Quality Assurance

Quality assurance or QA is focused on providing confidence that the company's quality requirements would be fulfilled, and it includes all the activities that the company has implemented to provide such confidence. Quality control, on the other hand, refers to the inspection aspect of quality management, specifically the techniques and activities used to meet the quality requirements.

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