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Val Miller demonstrates a volume gauge.

April 28, 2014

Office of Weights and Measures Sees Progress in 

Proficiency Testing

Byline: Curt Suplee, PML

Americans rely on many measurements of mass and volume in their daily lives, from weighing broccoli 

at the grocery store to putting gas in the family car. In order to ensure both consumer confidence and 

uniformity in commerce, the accuracy of the devices used in those measurements must be tested at 

regular intervals. The degree of accuracy achieved, in turn, ultimately depends on the competence of 

the metrologists who calibrate over 350,000 

measurement standards per year that are then used by 

weights and measures officials when testing measuring 

instruments.

Training and evaluating those personnel is the year-round 

responsibility of PML’s Office of Weights and Measures 

(OWM), and nationwide the demonstrated abilities of lab 

staff are trending upward. OWM has just compiled its 

summary training and proficiency-test data for 2013, 

which show the highest overall success rate on proficiency 

testing since the program began collecting data in 2006: 

98.97 % now, versus 92.76 % seven years ago.

That improvement is directly tied to OWM’s recent 

efforts. “All persons who work in a standards lab must be 

able to demonstrate proficiency in order for their labs to 

be recognized by NIST,” says Georgia Harris of OWM’s 

Laboratory Metrology Program. “Each of the 45 or 46 

active labs* is recognized with a certificate of 

measurement traceability to support their state legal 

requirements; they may also be accredited by NVLAP. When we issue a certificate, the facility, 

equipment, staff, standards, procedures – the whole system – is examined against international 

standards. A very big part of that process is training and proficiency testing (PT).”

A big part indeed. In 2013, OWM staff and highly trained volunteer instructors trained 446 students in 

seminars, 110 students in webinars, and 55 students in workshops for a total of 633 students. In 

addition, there were 14 proficiency tests conducted in conjunction with several of America’s six Regional 

Measurement Assurance Programs (RMAPs). Proficiency tests averaged 20 participants, each of whom 

took measurements of 10 different items, for almost 3,700 points of possible pass or failure.
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Georgia Harris with a mass scale.

Many factors have contributed to the rising PT success rate. “For one thing, we completely re-designed 

all our training courses over the past three years,” Harris says, “emphasizing adult-learning concepts and 

ensuring that the training is activity-based and hands-on.** Now when participants come in to our 

seminar on mass measurement, we issue them a test-weight kit on the first day, and they have to 

submit comprehensive calibration certificates on their measurements of those artifacts at the end of the 

two-week course. There’s no way to put it off or get more time.”

In addition, OWM has implemented a dynamic assessment scheme to respond to changes in student 

needs. “When we see an area develop a significant failure rate in an area of PT testing, we target it for 

more training in subsequent years,” Harris says. “In the volume-measurement category, for example, 

we started observing too many failures, so we began providing additional training for three consecutive 

years.” The numbers tell the story: In 2011, only 62 % of participants successfully passed the volumemeasurement PT; this year it was 89 %.

About 20 % to 30 % of PT participants are not from state 

weights and measures labs. They come from the military, 

DOE national laboratories such as Sandia and Oak Ridge, 

and industry. Pharmaceutical companies including Abbott 

Laboratories and Eli Lilly and Company have sent staff.

Similarly, the training program serves a broad community. 

OWM conducts training sessions both in the field and at a 

special educational lab on the NIST Gaithersburg, MD 

campus. “We have the only training facility of its kind in 

the world,” Harris says, “So we also get people from many 

other countries, including government and industry 

metrologists from Canada and Mexico.”

Training begins with a course in Fundamentals of 

Metrology. Passing a math exam is now a prerequisite. 

“Historically, the biggest challenge with our students has 

been their math skills,” says OWM instructor Val Miller. 

“Many of our students have been out of school for 10 or 

15 years and haven’t retained those skills. So we used to spend up to a day of remedial math exercises 

on simple thing like order of operations.”

Another area that typically requires review is correct use of units and symbols. “We spend a lot of time 

on that,” Miller says. “If you give a customer a calibration report with an error on it, it’s not simply 

wrong – it compromises trust and ruins your credibility. We start emphasizing that at the first session of 

our Fundamentals course, and keep it up throughout the program. The calibration certificate that goes 

out has got to be right.”

The entire basic course sequence takes four weeks, with two weeks spent on mass. (Ninety percent of 

all measurements done by state labs involve mass. Volume measurement makes up another 8.5 %.) In 
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addition, OWM conducts numerous specialty classes, offers webinars to improve skills and methods, 

and holds training sessions for trainers.

“At the end of the day, our goal is to assure traceability and uniformity in commerce,” says 

Carol Hockert, chief of OWM. “The only way for us to know whether or not our training is truly 

successful is by evaluating its implementation. Proficiency tests are an excellent way for us to measure 

success, so we will continue to improve and expand the use of PTs in our program.”

ENDNOTES

* With the exceptions of Rhode Island, Delaware, and North Dakota each state has a weights and measures lab. 

The District of Columbia also closed its laboratory about three years ago. However, Los Angeles County, Puerto 

Rico, U.S. Virgin Islands, and the U.S. Department of Agriculture, Grain Inspection Packers and Stockyards 

Administration maintain separate lab operations and are participants in the OWM program. “Active” labs are 

those which participate in the training, regional measurement assurance program training and proficiency testing, 

and submit requests for laboratory recognition according to NIST Handbook 143, Program Handbook.

** Last year, OWM was named an “authorized provider” by the International Association for Continuing Education 

and Training, which certifies that the OWM training program is compliant with internationally accepted standards.

Among its many activities, PML’s Office of Weights and Measures conducts training classes for trainers.