AQL General Inspection Levels: What are They, and How do You Use Them?

by | Jul 29, 2021 | AQL, Product Inspections, Quality Control

AQL (Acceptance Quality Limit) is an essential sampling method used to conduct product quality inspections at your supplier’s facility overseas. These inspections help you hold your manufacturer accountable so that you can avoid disastrous quality issues that might impact your profits or lead to brand damage.

If you’ve looked at the AQL chart, you may have noticed the AQL General Inspection Levels and wondered how they work. The three General Levels help determine how many units of your product to inspect. And below, we cover each one to help you understand how they impact your product inspections.

Table 1 of the AQL Chart

Table 1 of the AQL Chart

The 3 General Levels Explained

There are three General Inspection Levels (I, II, and III) on the first AQL table. The leftmost one, General Level I, will give you the smallest sample size, which means your inspector will check fewer products. The rightmost one, General Level III, will give you the largest sample size, which means they will inspect more.

The AQL General Inspection Levels on the AQL Chart

For example, let’s say you placed an order for 5,000 wooden picture frames and hired Insight to conduct inspections at your factory. During your AQL sampling inspection, if you used:

  • General I – The inspector would check 80 frames.
  • General II – The inspector would check 200 frames.
  • General III – The inspector would check 315 frames.

(Side Note: If you are unsure of how we arrived at these numbers, download our free AQL 101 guide to learn how to use the AQL chart.)

Wooden Picture Frames

So what purpose do these different sample sizes serve, and why would you choose one level over the others? First, there’s Level II, which is generally considered the ‘default’ inspection level.

Level II – This is Your Default Inspection Level

AQL General Inspection Level 2 on the AQL Chart

We recommend that you use General Inspection Level II as your starting point. And depending on your situation, you can either adjust it up to General III or down to General I. But for most circumstances, this level is appropriate.

Why might you decide to use Level I?

Level I – Choose This to Inspect Fewer Units

AQL General Level 1 on the AQL Chart

The benefit of inspecting fewer units is that your inspection will take less time. As such, it might cost less since inspection service providers like ours bill based on the ‘man-days’ required to conduct an inspection. On the other hand, you must understand that inspecting fewer units will lead to less confidence in the inspection result.

We recommend that you only drop down to General I when you have already been working with a factory for a considerable period of time. If they have produced consistent results and earned your trust, it can make sense to inspect fewer units.

Why might you use Level III?

Level III – Choose This to Inspect More Units

AQL General Level 3 on the AQL Chart

The benefit of using Level III is that the larger sample size will give you more confidence in the inspection result. However, if an inspection requires more ‘man-days’ to complete, it may increase your inspection costs.

You might consider using General III if you are working with a new supplier. Or, if you are working with a long-term supplier and they’ve had quality issues recently, you can inspect more units until the problem is rectified.

Which General Level is Appropriate for Your Product?

Choosing the most suitable General Inspection Level is important because it affects statistical confidence in your inspection result and can impact your inspection costs. As mentioned above, if you have a stable supplier relationship, consider lowering your General level. And if you’ve had quality issues or are working with a new supplier, consider raising it.

If you’d like more specific guidance regarding your situation, please reach out to us, and we can provide our recommendations.

What About the Special Inspection Levels?

The difference between the General and Special Inspection Levels is that the Special Levels will give you even smaller sample sizes. Your General Level applies to the inspection overall, while your Special level applies to any tests that might be destructive to the product, are time-consuming, or tend to yield similar results across the sample.

For more information, see our article about the AQL Special Inspection Levels.

Additionally, if you’d like to get a complete high-level overview of how AQL sampling works in quality control inspections, we recommend downloading our AQL 101 guide.

Free White Paper: AQL Inspections 101

As a consumer goods importer, the quality of your products is key to your success. Good quality products will earn you favorable reviews and repeat purchases. Thus, product inspections are important. AQL determines the sample size for your inspections and understanding it is important. Having a good grasp of this method allows you to work with your third-party inspectors more effectively. This white paper will teach you all the basics of the AQL method.

Thanks for reading! Do you have any questions about the article? Is there something else you’d like to add? Leave a comment below.

Andy Church

Founder & CEO, Insight Quality Services

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