QR Code quality of the printed symbol as a predictor of the likelihood the symbol will work properly is a much different issue than for example the quality of a UPC or Code 128 symbol.

The environment in which a UPC symbol exists is a very controlled one. The design engineering of the symbol is subject to an ANSI/ISO specification—this is one attribute that is shared by the QR Code, which is also defined by an internationally recognized standard. But that is where the similarities end.

QR Code Quality as a predictor of performance  is much more than just the quality of the printed symbol

A UPC symbol is scanned by devices (scanners) whose design and performance is also defined by international standards. There may be subtle differences in scanner optics and decode algorithms, but these are minor performance variations within an overall compliance to the ANSI/ISO specification.

On the other hand, a QR Code that complies with ANSI/ISO specifications is not used in a standardized scanning environment. Smart phones vary widely not only in the in the decode algorithms and optics they use; varying operating systems handle and calculate the data differently. Currently there are at least six different operating systems in use. Smartphone camera optics vary even more; there are plastic lenses, high quality optical grade glass lenses, auto-focusing lenses, fixed focus lenses; even very high quality smartphone camera optics are subject to dirt and damage which degrade performance.

QR Code Quality must include considerations of smartphone scanning

As of this writing there is no known movement toward scanning standards for smartphone cameras such as exist for barcodes in the retail channel or supply chain.

If all of this sounds a bit like the Wild West, well it is—but even in the Wild West there were some generally accepted practices and conventions.

Probably the most often overlooked one is code density—the number and size of the black modules that form the QR Code.  Theoretically the code can contain huge amounts of information in a very small space, if the modules are very small. But if the print technology cannot resolve the small elements, the code will fail no matter how fine the smartphone optics or decode algorithm. Lower quality printing such as newspaper or magazine print advertizing should employ larger module sizes.

The most overlooked aspect of printed QR Code Quality is code density

This can be helped by encoding smaller amounts of data; if the encoded data is a URL, it is wise to use a short URL if possible.

One solution is to use a URL shortening service but beware: some public hotspots such as libraries, restaurants and airports block such services. Some URL shortening services do not allow the owner/publisher of the QR Code to access their performance statistics. URL Shortening services sometimes stop working—sometimes because the companies aren’t in it for the long run, sometimes because the ISP’s shut them down for questionable (spamming) practices. This isn’t to say the shortened URL’s should never be used—but they add another layer of risk to an already complicated environment.

Another very common mistake is for a QR Code publisher to fail to create a landing page specifically designed for a mobile device. Pointing to an existing web page is often illegible on a smartphone.

These are not reasons to avoid using a QR Code. Q Code can be an important and productive tool in a marketing campaign—but it’s another way of accessing the same data from a mobile device.