Fixating on numbers can be hazardous to your accuracy.

While it has yet to make the psychiatric profession’s growing list of common maladies, the condition I call “digital disease syndrome” continues to rapidly spread. The first sign of a patient's affliction with digital disease is abnormal concentration on the digits to the extreme right of the decimal point on a digital readout. This is the opposite of the disease that afflicts government officials in which the focus is on digits to the far left of the decimal.

You’ll know the afflicted by their symptoms. These include glazed eyes as they bandy about millionths of an inch or parts of a micron in conversations concerning measurement. In severe cases, an afterglow from red or green LEDs may be evident in the cornea of the eyes. In the type “B” permutation, a dull off-white color may cover the eye with small rectangular black segments that flicker on and off.

The insidious nature of this condition is such that it spreads exponentially. It develops from believing the measurement-tool myth that says increased resolution equals better accuracy. While there is a link, blind faith in small numbers puts many folks in need of therapy to quell the violent tendencies that develop as a result of digital disease. Fights over measurements can break out and occur most frequently when the resolution of the equipment involved defies the realities of metrology, but the afflicted still cling to their numbers.

To paraphrase a government representative, in metrology, “A digit here and a digit there. Pretty soon you’re talking about unreal numbers.”

If anyone would be thought to be immune to digital disease, one would suppose it to be calibration laboratory metrologists. After all, they have the wisdom and experience that should serve as an “inoculation” against the affliction. Not so. Calibration laboratory metrologists are as susceptible to digital disease as other metrologists. That’s because carriers of digital disease are everywhere; the lowly micrometer can transmit the illness just as readily as can fully automated gage-calibration equipment.

I recently read a promotional brochure for a dimensional calibration device where the biggest characters on page one related to the alleged resolution of the tool. When I finally found an accuracy statement, in the fine print on the last page, it showed error in the unit to be about 40 times the resolution. And that’s before accessories are bolted on so that a user can actually measure a part. Marketing people and tool suppliers probably create brochures in this way to ensure a manufacturer pays attention to the specifications.

Even relatively practical digital resolution has to be considered with caution. One must always remember that the stated accuracy of the measurement tool refers to the tool when it is in a cold and pristine environment, such as in a tool maker’s laboratory. All bets are off when that tool is put in a manufacturer’s hot little hands for use in the typical work environment.

I don’t want you to think I’m against digital displays; even I can read them. And I have to admit they can be seductive when they’re sitting there with their segments innocently blinking. But the trick is to keep your focus and avoid being dazzled by them.

One way to do this is to assume that the last digit may be not be particularly significant in real terms. Protect your health. Don’t go into battle over measurements with your last digit as your only weapon. You could end up with zeros for ammunition. And, never assume that digital resolution is any indication of the accuracy of the tool, let alone the measurement you’re trying to obtain. .

If these tips don’t relieve the symptoms of digital disease syndrome, switch the measurement tool off, take two aspirin and call me in the morning.