What is a National Measurement Institute?
NIST is the national measurement institute (NMI) for the United States. Also sometimes called a national metrology institute, an NMI is a unique organization authorized by a country’s government to:
- maintain the country’s primary measurement standards
- provide traceability for all national measurement needs
- represent the country in the international system of units for trade and science
- advance measurement science to support the country's economic competitiveness
- use measurement expertise to support the development of technically sound documentary standards
Everything in science and technology is based on measurement. Everything we use every day relies upon accurate measurements to work. NIST ensures the measurement system of the U.S. meets the measurement needs of every aspect of our lives from manufacturing to communications to healthcare. In science, the ability to measure something and determine its value — and to do so in a repeatable and reliable way — is essential. NIST leads the world in measurement science, so U.S. businesses can innovate in a fair marketplace. We use measurement science to address new challenges ranging from cybersecurity to cancer research.
Primary measurement standards define physical units, such as the meter or the kilogram (or the inch or the pound). The measurement units for weight and length need to be the same wherever you are in the country or the world, and primary standards are essential to ensure that.
NIST maintains each of the seven major units of measurement that we use in our daily lives. If you need to know exactly what time it is, the precise mass of a kilogram or the exact length of a meter, NIST can tell you.
These standards are not very useful just sitting in NIST labs. By comparing the measurement standards of users with the primary standards, we “disseminate” these accurate measurements to industry, academia and ultimately consumers, so they can be confident they have accurate measurements. NIST is the basis of an “unbroken chain” of measurements from the primary standards to the American people and U.S. businesses. These comparisons are called calibrations.
Traceability is a complex scientific concept, but it essentially means that NIST sets specific and precise standards, and then others carefully trace their measurements back to our standards by direct comparisons. The process of tracing those measurements back is called calibration.
Let’s look at an example of mammograms. Mammography machines must expose patients to the smallest amount of radiation needed to get a good image, so as to protect the patient from unnecessary exposure. This ensures the benefits of the test far outweigh the risk from minuscule exposure to radiation. Nearly 9,000 U.S. mammogram facilities trace the amount of radiation in their mammography machines through a chain of calibrations all the way back to one of our radiation physics labs here at NIST in Gaithersburg, Maryland. So, hospitals know the exact amount of radiation a patient is being exposed to because of those precise measurements and chain of calibration.
There’s an enormous international infrastructure designed to ensure that measurement systems work together and are mutually acceptable worldwide. Without it, our global economy simply couldn’t function.
Countries around the world agreed to the Treaty of the Meter in 1875, which allows the world’s NMIs (equivalent organizations to NIST) to work together to ensure that the way things are measured in the U.S. is acceptable in other countries and vice versa. Without this engagement by NIST, U.S. companies could not export their products or trust products made in other countries. NIST sends a representative to the International Committee on Weights and Measures (CIPM), which oversees the global measurement system, known as the International System (SI) of Units.
This global cooperation means countries can trust each other’s measurements, a vital requirement for worldwide commerce. This confidence is essential for everything from repairing airplanes to buying materials for your company across the globe.
NIST has the most advanced and extensive research program in support of measurement science in the world. We have the most precise clocks that deliver the time to your phone or smart device. We’re leading the way to safer artificial intelligence. Our cutting-edge science has been used to keep you safer and healthier.
As part of the Department of Commerce, a major part of our mission is to help American businesses thrive. For example, the U.S. is re-establishing its leadership in computer chip manufacturing, and NIST’s researchers are playing a significant role in this effort.
Additionally, NIST is working on advanced communications efforts, such as 5G wireless communications systems for cell phones and other devices. We also provide a solid foundation of measurement science that enables health and bioscience innovations, like modeling the movement of microplastics through the human gut. Our research is contributing to the development of powerful quantum computers that may be used in the future in health care, finance, manufacturing and more.
Documentary standards are, as their name implies, documents. They provide an agreed-upon way to carry out a technical process, from measuring the radiation dose to a cancer patient to establishing food safety management procedures. NIST is engaged in over 1500 standards writing activities providing technical expertise.
Documentary standards are developed by experts in a particular subject area and typically approved by a recognized professional organization, which then publishes them for the world to use. Documentary standards are like highly technical recipes that we all follow. Instead of making a delicious cake, we’re getting important measurements the world needs for science and commerce.
One of NIST’s best-known documentary standards is the NIST Cybersecurity Framework. The framework allows users to assess their cybersecurity risks and follow best practices. NIST is also currently developing documentary standards for post-quantum cryptography – a defense against potential cyber attacks from quantum computers.