Keepers of the Right Answer: Why Measurements at NIST Are Important for the Nation and the World

Practically everything you use in your everyday life works because of measurement science. Without precise measurements, your car wouldn’t run, your phone wouldn’t work, hospitals couldn’t function, and the ATM would fail.  

NIST is the national measurement institute of the United States. Most people in the U.S. have no idea that there is a single organization within the federal government that makes sure all measurements in the U.S. are correct and trustworthy — and that they are accepted by other governments worldwide.

What does that look like in practice? Here’s an example.

More than 40 million mammograms are done in the U.S. each year. Each one is a chance to save a life.  

Those mammograms have to be both safe and effective, so mammography machines must expose patients to the smallest amount of radiation needed to get a good image, thereby minimizing any harmful effects. Careful measurements ensure that the benefits of the test far outweigh the impact of a minuscule exposure. We know that U.S. hospitals achieve this balance because they trace that radiation amount back to one of our labs here at NIST. 

Traceability is a complex scientific concept, but it essentially means that in comparison to precise standards calibrated at NIST, the mammography machine accurately delivers the exact amount of radiation allowed. We know this because the chain of calibration — or all the steps it took to test and check that machine — can be linked all the way back to one of our radiation physics labs here in Gaithersburg, Maryland.  

This is one of many hundreds of examples of how measurement science, also known as metrology, affects daily life — whether you think about it or not.  

Some of these examples are obvious. When you fill up your car’s gas tank or buy deli meat, you know exactly how much you’re buying because the state weights and measures offices check the pumps and scales for accuracy, based on the volume and mass standards from NIST.  

Perhaps less obvious is that the values on the nutrition labels on food packaging are determined by comparing the values to the food standards that NIST produces. Even less obvious is the fact that your GPS works because of the atomic clocks inside the satellites. NIST created the world’s first atomic clock and remains a world leader in making these ultraprecise timekeepers. 

Why Measurement Science Matters 

These examples — and many more complicated ones — are why we have a national organization focused on metrology. We have thousands of researchers, known as metrologists, constantly figuring out how to measure things better.  

Why such dedication? Well, everything in science and technology is based on measurement. In science, the ability to measure something and determine its value — and to do so in a repeatable and reliable way — is essential.  

For example, precision measurements enable weather forecasting to happen. While you may notice it more when the weather forecasts aren’t quite right, five-day weather forecasts are now accurate about 90% of the time.  

One tool meteorologists (as opposed to metrologists) use to predict the weather is measuring the energy — or radiation — that’s coming from Earth. Recent advances in our ability to make these measurements more accurately have contributed to our ever-improving ability to predict what your weekend weather will be like.   

Additionally, the more science and technology advance, the trickier the measurements become. 

For example, when scientists in the late 1940s created transistors — which have become the building block of computers and virtually all modern electronics — they had to measure them on the scale of the millimeter, which is about the thickness of a dime.   

As semiconductor technology has advanced, we now have to measure computer chips at the scale of nanometers — one billion times smaller than the width of that dime. So, if measurement science didn’t improve, technology couldn’t advance. Without it, we would not have the latest smartphones we take for granted today.  

An additional challenge is that we’re now in a world where day-to-day measurements are tied to physical constants in nature, not to things. This makes measurements more universal and consistent and also more complicated for scientists to define.  

For example, before 2018, all mass measurements were traceable to a metal cylinder held in a vault in France. Now, mass is determined by a physical constant in nature — known as the Planck constant. While this new approach has many benefits, it’s also more complex. In fact, researchers here at NIST are collaborating with our counterparts in Germany to work out some of the remaining challenges with this particular measurement. 

One of the things I love about working in metrology is that there is a correct answer to any measurement question. If we are careful enough and understand the science well enough, then we will get a reliable answer. We will also be able to know how sure we are of the accuracy or correctness of the answer, which we call “uncertainty.”  

One of the roles we play at NIST is to provide those answers in a trustworthy way; that’s why I call us the “keepers of the right answer.” If someone needs to know a temperature, what time it is, how pure something is, or how small something is, they know they can trust the science that comes out of NIST.  

 I’m proud to be a part of that process and to have helped lead the organization that inspires trust across the world.  

From Physicist to Global Metrologist  

In school, I studied atomic and molecular physics, and I knew I wanted to work in a laboratory.  

When I drove up to my first day at NIST a few decades ago and parked outside of the metrology building, I realized I had no idea what the word “metrology” meant.  

I went to my office and looked up the word in the dictionary. I learned it meant the science of measurement. That’s interesting, I thought. 

I went on to do physics research in my lab in support of the semiconductor and electricity industries. These experiments obviously involved measurements, as all science does, but honestly, they were not the focus of my thinking.  

It wasn’t until I was asked to work on calibrations that the importance and beauty of measurements became clear to me. Working on calibrating electrical transformers and capacitors (devices that store energy), I delved into the world of traceability. I saw how important and universal the world of metrology was. 

One of the most exciting outcomes of my engagement with calibrations was that I became involved in the international world of metrology. Other countries have their own versions of NIST — other national metrology institutes — that handle their own weights, measures, timekeeping and related areas of science.  

There’s an enormous international infrastructure among the countries of the world and their national metrology institutes to make sure the way things are measured in the U.S. is acceptable in other countries and vice versa. This is essential for issues like repairing airplanes or buying materials for your company across the globe.  

As the chief metrologist for the United States, I personally get to see the importance of this global cooperation and to be a part of a worldwide community of metrologists. While to many this world of measurements may seem mundane or even boring, there are so many exciting things happening.   

The redefinition of the second is expected to come in a few years. (This will be big for metrologists, but don’t worry, you’re unlikely to notice.) New measurements to monitor the climate are being developed and deployed. Techniques to unravel the mysteries of bioengineering are advancing. Ways to accurately measure the presence and impact of microplastics are being developed, and so much more.  

As technology advances and demands more from measurement science, we will be here to provide it. It is really an exciting time to be a metrologist!