What are the General Inspection Levels? How to choose the correct level for inspection?

In addition to setting the AQL, the buyer should choose the sampling plan from the different inspection levels, here we break down the main sampling options for quality control inspection, to help guide you determine scope of inspection that is best for you and your product.

Sampling 

Using statistical sampling based on acceptable quality limits (AQL), acceptance sampling decides the sample sizes for different order quantities, and these different sample sizes are the origin of GI, GII, and GIII.

General Inspection Levels

These main inspection levels – “GI”, “GII” and “GIII” – stand for general inspection level 1, 2 and 3, respectively. These three different levels indicate sample sizes of one lot size for a non-destructive inspection. The sample size of general inspection levels is applied by the inspector to the workmanship of the products during visual inspection. Any defects found in terms of workmanship are taken into account in the AQL result of the inspection. Any professional AQL chart will show the GI, GII, and GIII sample size of each group of lot sizes.

Reduced inspection (or level-I inspection):

Has this supplier passed most previous inspections? Do you feel confident in their products quality? Instead of doing no quality control, buyers can check less samples by opting for a level-I inspection.

However, settling on this level by default, less samples are inspected. This inspection level is appropriate when the client is confident that the quality of the products is acceptable.

Normal inspection (or level-II inspection):

It is the most widely used inspection level, to be used by default.

Tightened inspection (or level-III inspection):

If a supplier recently had quality problems, this level is appropriate. more samples are checked. This inspection level is used for suppliers that recently had severe quality problems, or for high-value products. It can also be interesting for small quantities, where the inspection would take only one day whatever the level chosen.

Example to get an clearer understanding

Lot Size General Inspection I
(GI)
General Inspection II
(GII)
General Inspection III
(GIII)
2,000 50 125 200

However, the lot size is not the only factor at work when determining the sample size. There are many other elements that need to be taken into account, we can discuss these elements later.



1 Comment

  • Meltrick torres

    Hello, please help me redeem my quiz points from my QC2 professor. On her question, she said that what if the trusted distributor failed their last batch, and the machines they use is of very poor quality because of lack of care. Almost all of us used General inspection level 3, and the tightened inspection table. But she said that we still use the general inspection 2 and the normal inspection table. Why is that? Please help us, maybe that should be considered because the distributor’s
    Machinery is of poor condition so we should tighten inspection

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