QA, QC & Testing

Waste of Quality Control?

Quality Control can be hideously expensive and therefore it is prudent to reduce the amount of quality control used. Without impacting the quality of the product produced.

Consider a chocolate manufacturer who produces tens of thousands of chocolates each day. By adopting stringent quality control procedures the manufacturer would have to get every chocolate produced tasted. The tasting would spoil the chocolates and they would therefore be required to be thrown away.

Not only is this costly in terms of the number of chocolates being thrown away but the added expense of the people required to Quality Control the quality, that is taste the chocolates.

By only checking a selection of chocolates produced in each batch, the level of Quality Control undertaken is substantially reduced and only a very small amount of chocolates are spoilt by tasting. Yet an excellent standard of Quality Control can still be achieved by adopting this approach.

Quality Control is expensive however costs can be reduced without affecting overall product quality.

Quality Assurance And Quality Control Working Together

Whilst Quality Control and Quality Assurance are used in different ways, they can help each other out immensely.

It's not only the level of Quality Control that's important in reducing costs without affecting quality but the level and quality of the Quality Assurance used.

The better and more frequent use of Quality Assurance, the less need to adopt unnecessary levels of Quality Control. This ultimately leads to savings from reduced Quality Control.

Quality Assurance can reduce the Quality Control overhead.

Consider a car engine manufacturer who outsources pistons from local suppliers. The Quality Control used to determine whether the engine has been built to a high quality standard, involves running a car with the new engine around a test track.

Every engine produced and fitted to the test car blows up when taken round the test track, thus leading the engine to be scrapped.

The reason is down to the piston heads having a circumference which is between 25 to 50 microns more than required. This leads to the piston heads rubbing against the piston walls in the engine and overheating, causing the engine to explode.

The cost to the engine manufacturer is immense as every engine produced fails Quality Control and has to be scrapped. Yet this loss can be stopped dead in its tracks, leading to the amount of engines blowing up reduced dramatically.

By adopting better Quality Assurance procedures and increasing the amount of Quality Assurance, the piston heads can be measured more accurately by either calibrating the equipment used more stringently or using more accurate equipment which is checked for accuracy more frequently.

Maybe there is no measurement of the piston heads currently undertaken, so this must be included in the Quality Assurance process.

By increasing the likelihood that pistons produced will be the required size, the level of failure, that is engines blowing up during Quality Control can be drastically reduced.

Better Quality Assurance reduces the level of failure from Quality Control.

The cost of improving Quality Assurance is far less than the costs of writing off products that fail Quality Control.

Many organisations under estimate the importance of having both Quality Assurance and Quality Control in their workplace. By adopting one or the other, they end up with additional costs leading to losses which are easily avoidable.

Both Quality Assurance and Quality Control are needed together as using one or the other can increase costs.

By getting Quality Assurance and Quality Control to work in unison, the quality of products produced increases as well as the potential for profit.

How can Quality Control be used to determine the quality of a product?

By checking a product to see whether it is what is expected, can the quality of that product be determined. In the next section the Requirements, what is expected from a product, is discussed in detail.


 • Quality Control is checking what's produced is acceptable.

 • Too much Quality Control can be expensive therefore it is essential to determine the exact amount of Quality Control required.

 • Quality Assurance can reduce the level of Quality Control needed.

 • Ideally both Quality Assurance and Quality Control are needed to improve a products quality.