Barcode Verifier Discrepancies

You have a verifier and so does your customer, but the two don’t agree. What to do?

Different verifiers will produce varying results. This is not uncommon. Expect slight discrepancies. Major discrepancies should not occur. When they do, which verifier do you believe?

But first, where is the line between a slight discrepancy and a major one? It’s difficult to provide a simple answer regarding a specific ISO parameter, but the final symbol grades should be the same. Deviations of one grade level, where one verifier reports an ANSI B grade and another reports an ANSI C grade, can be acceptable if the B is a low B and the C is a high C. Here is where ISO fractional numerical grading is helpful. A B versus C grade discrepancy sounds bad, but if the ANSI B is ISO 3.0 and the D grade is ISO 2.9, that is reasonable. What’s acceptable? I’ll go out on a limb and say that a .5 or more ISO discrepancy is unreasonable on any parameter or final symbol grade. A two-grade discrepancy, like C versus F, is unacceptable.

Which verifier do you believe?

Bovine Detritus

Don’t default to the one with the better grade! Choosing the better grade is not risk management—there’s another word for it that involves farm animal excrement. Here’s how to sort which verifier is telling the truth:

With each verifier, scan a reference standard barcode. This can be a retained barcode with a verification report, or a calibrated conformance standard test card from a certified metrology test target supplier. The verifier that detects and reports each parameter within tolerance wins.

Golden Barcode

If you don’t have access to a reference standard barcode, here are some other considerations for why verifiers might disagree:

• When was each verifier last calibrated? Believe the one with the most recent certificate of ISO compliance.
• Are both verifiers grading to the current ISO standard for the barcode type? 2D barcodes grade to ISO 15415. Linear barcodes grade to ISO 15416. Different versions of an ISO standard calculate parameter grades differently. Believe the verifier using the current version of the applicable ISO standard.
• Do both verifiers eliminate ambient light influence? Believe the one that does.
• Do both verifiers scan the barcode at a fixed angle and distance? Believe the one that does.
• Are both verifiers relatively clean? Dust and dirt on the exterior can mean dust and dirt in the optical path. Beware! A cleaner verifier might not produce a higher grade, but could be the one to believe.

Finding Trust

These are some ideas for how to decide which verifier to trust, when two (or more) verifiers disagree. There are other circumstances when it’s tempting to get a “second opinion” when a verifier is failing a barcode, not a discrepancy between two verifiers. Almost every week we get a call from someone whose verifier is failing a barcode, but their scanner or smartphone reads the barcode without a problem. They are looking for absolution. They are finding something else–liability.

In these cases, always believe the verifier, always ignore the scanner or smartphone, and take immediate steps to validate the verifier’s performance:

• Calibrate it
• Scan a known barcode and compare the results to the saved report
• Purchase a calibrated conformance standard test card and use it to periodically validate your verifier’s accuracy.

Contact us with questions or to schedule a free 15-minute consultation.