“It is better to be vaguely right than exactly wrong.”

Carveth Read wrote that sentence in his 1898 book Logic: Deductive and Inductive.1Although Read was not specifically referring to scientific measurements, the sentiment is the same — a high-precision instrument that is not properly calibrated will be very consistent at giving you the same wrong answer. Avoiding this conundrum is why mutually agreed upon calibration standards are so important.

The National Institute of Standards and Technology (NIST) has been setting measurement standards in the US since 1901. NIST, in turn, has the responsibility of keeping the United States measurement standards in agreement with the International System of Units (AKA “Le Système International d’Unités” or “SI” for short).

Precision vs. Accuracy

There is a difference between precision and accuracy. A measurement that is high accuracy but low precision may have a wide margin of possible answers, with the correct value somewhere in that range. A measurement that has high precision and low accuracy yields a narrow range of values, with the answer probably not within that range.

The upshot of this is that a precision instrument is of no use unless it is properly calibrated, and calibration requires standards.

Hence the existence of NIST, which has three core activities:

  1. Develop new measurement technology
  2. Set standards of measurement
  3. Develop methods to trace measurements back to those standards

Traceability is the critical issue when it comes to instrument calibration. Accurate communication of technical information relies on traceability. In order for an instrument’s measurements to be both precise and accurate, there must be an unbroken path of calibrations that leads back to NIST standards.

Standards Are Our Business

Applied Image can assist you in NIST certification and maintaining NIST traceability. NIST certification and documentation is available as an option for all our calibration aids. You need the right calibration standards for your application. We can guide you through the hundreds of off-the-shelf components in our catalog to find exactly what you need. If it doesn’t already exist, we can make a custom calibration standard for you using our proprietary ACCUedgeTM technology. We have the facilities to perform routine recalibration of our existing calibration standards, as well as certify or cross-check your existing components. You’ll never be “exactly wrong” ever again.

To learn more, download our eBook “Calibration, Care & Cleaning of Your Stage Micrometer.”