THE THREE AQL GENERAL INSPECTION LEVELS

There are three general AQL inspection levels: “GI”, “GII” and “GIII”. Each indicate sample sizes for a non-destructive inspection.

The inspector generally inspects the entire sample size for quality issues related to performance, function and visual appearance. Any quality defects found during inspection contribute to the overall “pass” or “fail” result.

You can find GI, GII and GIII sample sizes for your lot size in the AQL table. This first part of the AQL table helps you determine your AQL inspection level and sample size. We’ll explain later how the second part of the table helps you determine how many defects you should accept in the sample size.

Higher inspection levels generally correspond to larger sample sizes, with GIII being the highest.

For example, let’s consider a lot size of 5,000 pieces, represented in the table below within the range 3,201 to 10,000. The three inspection levels each result in a different sample size, denoted by a different letter—“J”, “L” and “M” in this case.

These letters correspond to three different sample sizes—80, 200 and 315 pieces, respectively, as shown in the second part of the AQL chart below.

GI inspection level

GI inspection level offers the smallest sample sizes of the three general inspection levels. Considered the “budget option”, GI may be your best option if you’re particularly short on time or money.

GI may be adequate in cases where:

• You have strict budgetary constraints and can’t afford to send an inspector to inspect for longer than one day
• Products are of low value, such as promotional goods, or pose minimal safety risks
• Suppliers have a strong quality management system based on ISO 9001 and a long and consistent history of meeting your requirements

Using the 5,000-piece lot size above, let’s say you choose the GI sample size of J, or 80 pieces. This sample size then also influences the number of defects you can accept in your order.

To determine your accept and reject points, you must first set your acceptable quality levels for each defect type (related: 3 Types of Quality Defects in Different Products). Just as your tolerance for defects can vary by the severity of each defect, so too should your acceptable quality level for each.

Many importers set acceptable quality levels of 4 or lower for “minor” defects for consumer goods. You might similarly choose an AQL of 2.5 for “major” and 0 for “critical” defects, indicating a lower tolerance for these more severe defects.

Let’s say you choose an AQL of 2.5 for major defects in our current example. You would then have an accept point of 5 defects and a reject point of 6 defects in the inspected sample of 80 pieces.

You can raise or lower your acceptable quality levels based on your tolerance for quality defects. Remember, the higher your acceptable quality level, the higher your tolerance for quality defects in your order.

GII inspection level

Inspection companies sometimes refer to the GII AQL inspection level as a “normal” sample size. GII is the inspection level importers most often choose, as GII achieves wider coverage scope with relatively low cost.

GII inspection level is often especially fitting for the first inspection of a lot. Seeing these first results can help you determine if GII is still suitable going forward, or if you should raise or lower your inspection level.

Now let’s look at how a GII sample size of L, or 200 pieces, would influence the accept and reject points for your order of 5,000 pieces.  

The accept and reject points generally increase with the sample size, assuming your acceptable quality levels stay the same. So with an AQL of 2.5, your accept point increases to 10 defects, and your reject point increases to 11 defects.

GIII inspection level

The GIII inspection level provides the largest sample size for your lot out of the three AQL inspection levels. Compared to the GI sample size of 80 units for a 5,000-piece lot size, the GIII sample size is nearly four times as large—315 pieces.

This general inspection level offers the largest scope and greatest assurance of order status and quality with acceptance sampling. Thus, GIII minimizes your risk of unknowingly accepting a shipment with a higher portion of defective pieces than found during inspection.

Returning to your 5,000-piece lot size, a GIII sample size of 315 pieces would lead to an accept point of 14 defects and a reject point of 15 defects.

You might consider using a GIII AQL inspection level if:

• Your supplier has a history of poor quality
• This is your first order with a supplier
• This is the first order of a newly developed product ; or
• The product is of particularly high value (e.g. luxury goods) or poses particularly high risk (e.g. fragile goods)

Some importers might find this inspection level cost prohibitive, as it will take the inspector more time to check more goods.

Carefully consider the factory’s quality history, available inspection manpower and QC budget when determining whether to use the GIII inspection level for your order.