How to Randomly Select Cartons During an Inspection Process

Published
January 2017

 The apparel and footwear industry outsources most of its components and products. This means companies selling apparel and footwear import finished goods from  developed, industrialized countries and also from developing countries. This further means that quality and compliance inspections are imperative to ensure products meet requirements.

 

During any inspection process of apparel and footwear, you want to choose cartons of completed and packaged products in a random manner to ensure you get a valid sample of the entire order. Random sampling ensures your findings are representative of the whole order.

 

Here’s how to randomly select cartons to be inspected.

 

  1. Ensure the apparel and/or footwear order is complete and packed. This may be a point of contention for some inspectors who will inspect partial orders and follow up with an inspection of the remaining cartons after they’re completed and packed. While this method is possible, it’s more accurate to take a random sample of the whole rather than parts.
  2. Determine the number of cartons to be selected. An industry standard is to use the square root of the total cartons. For example, if you have 200 cartons total of apparel or footwear, the square root is somewhere between 14 and 15 cartons.
  3. Make sure you have easy access to all cartons. If the factory stacks boxes of apparel or footwear all the way up to the ceiling, you’re going to have a hard time selecting random boxes from the middle, inside, and bottom.
  4. Choose the cartons. This can be done in two ways. First, you can randomly select carton numbers such as 3, 10, 17, 23, 32, etc. If you choose this method, avoid using any pattern such as all even or odd numbers, or counting by 5’s or 10’s. The second way to select cartons is to randomly pick from all sides of the stack and from the bottom, top, and middle.
  5. Randomly select individual apparel or footwear products from your selection of cartons. Using the same process above, determine how many pieces of apparel or footwear you need to inspect using the square root method. In the example of 200 cartons, if each carton contains 160 pieces, you would select 13 products from each carton. Again, randomly select them from the top, bottom, sides, and middle of the carton.

 

What Not to Do

 

Sometimes an inspector will come into an apparel and footwear factory and ask for a certain number of cartons, allowing the manufacturer to choose the cartons. This negates the effectiveness of a random sample because it allows the factory to choose specific cartons of apparel or footwear that they know contain good pieces.

 

Also, this doesn’t allow the inspector to check for water or other damage and to ensure cartons are all the same size.

 

By skipping the most important step of random sampling, the inspector might miss significant issues in the completed apparel and footwear, and report that defects are below the AQL limits.

 

Conclusion

 

Random sampling takes time. Some apparel and footwear companies are surprised by the significant time inspectors spend in sampling and counting, wondering how they can cut that down. This is not advisable because it puts the validity of the inspection’s findings at risk.

 

There may be an instance where you’ve worked with a manufacturer for several years and don’t have problems with unethical behavior or significant defects in apparel or footwear. In this situation, you might make a business decision to allow the manufacturer to set aside a certain number of cartons for inspection.

 

This is rarely the case, however. It’s important that your inspection process be valid. To ensure the process's validity, make sure it includes the steps above, and make sure the inspector does the picking.