No, this isn’t about promises you made on New Year’s Eve and broke the next day. It’s about measurement resolution—the number of decimal places to which a measured value is calculated and presented. The measurement can be of any parameter—voltage, distance, weight, temperature, whatever. The principle of measured and displayed resolution applies in all cases.

You may think that lots of digits after the decimal point means high-resolution measurement. If a device shows more digits to the right of the decimal, does that mean it has a higher resolution than one with fewer digits? Maybe; maybe not. Those extra digits to the far right of a display that are beyond the actual resolution of the measuring device are defined as empty resolution. They’re more for show than for performance.

What’s the right resolution?
A number of factors come into play when choosing the right resolution for a measurement. A common one is the 10:1 rule, which states that the measurement resolution should be 10 times finer than (or 1/10th) of the specification being measured. In other words, if the specification is 2.3 units, the measuring device should resolve to X.XX units, or one more decimal place than the specification. You might think that if one more digit is good, then two, three or more than that would be even better. Maybe not.

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