DAY 21 — MEASUREMENT RESULTS

What is a measurement result?

A quantity value attributed to a measurand together with other relevant information

What does a measurement result generally include?

Measured quantity value and measurement uncertainty

What VIM reference is shown for the definition of measurement result?

VIM 2.9

What is the measurand?

The quantity intended to be measured

What question should be asked when starting with the measurand?

What exactly am I determining?

What is a measured quantity value?

A quantity value representing a measurement result

What VIM reference is shown for measured quantity value?

VIM 2.10

What warning is given about an indication?

Do not automatically treat an indication as the final measured quantity value

What sequence can a calibration involve?

Indication → corrections or calculations → measured quantity value → measurement uncertainty → reported result

What determines the exact process from indication to reported result?

The measurement model and method

Why does measurement uncertainty matter?

A measured value is generally an estimate of the measurand

When is the result generally complete?

When the associated uncertainty is considered and reported as appropriate

What GUM reference is shown for this point?

GUM 3.1.2

How does the infographic distinguish error from uncertainty?

Error is measured quantity value minus reference quantity value while uncertainty is dispersion of quantity values attributed to the measurand

What is the formula for error shown in the infographic?

Error = measured quantity value − reference quantity value

What is the definition of uncertainty shown?

Uncertainty is the dispersion of quantity values attributed to the measurand

Are error and uncertainty the same?

No error is not equal to uncertainty

What is the reference value in the illustrative calibration example?

100.00 °C

What is the UUT indication in the illustrative calibration example?

100.12 °C

How is the error calculated in the illustrative calibration example?

Error = 100.12 − 100.00 = +0.12 °C

What combined standard uncertainty is used from the previous uncertainty evaluation?

u_c = 0.0735 °C

What coverage factor is assumed in the example?

k = 2

How is expanded uncertainty calculated in the example?

U = k × u_c

What is the expanded uncertainty before presentation rounding?

U = 2 × 0.0735 = 0.147 °C

What is the expanded uncertainty for presentation?

U = 0.15 °C

What reported result is shown when the measurand is temperature?

100.12 °C ± 0.15 °C

What values accompany the reported result?

U = 0.15 °C and k = 2

What does ±0.15 °C mean in the example?

It is the expanded measurement uncertainty

What does ±0.15 °C not mean?

It is not the error not the tolerance not the MPE and not automatically a PASS/FAIL limit

What should a technician check about the measurand?

The measurand should be identified

What should a technician check about the measurement model?

The measurement model should be checked

What should a technician check about the measured quantity value?

The measured quantity value should be checked

When should corrections be checked?

Corrections should be checked when applicable

What should be checked about units?

The units should be checked

What should be checked about measurement uncertainty?

The measurement uncertainty should be checked

When should the coverage factor be checked?

The coverage factor should be checked when applicable

What reporting information should be checked?

Relevant reporting information should be checked

What common mistake involves only reporting the display reading?

Reporting only the display reading without understanding the result

What mistake involves confusing indication with measured quantity value?

Confusing an indication with the measured quantity value

What is a reporting mistake involving the measurand?

Reporting uncertainty without identifying the measurand

What is the difference between error and uncertainty?

Error is a difference involving the measured quantity value and reference quantity value while uncertainty describes dispersion of quantity values attributed to the measurand

What rounding mistake is identified?

Rounding too early

What warning is given about declaring PASS/FAIL?

Do not declare PASS/FAIL without the applicable requirement and decision process

What should a calibrator ask instead of only asking what number the instrument showed?

Ask what quantity is being reported how the result was obtained and what uncertainty belongs to it

Why is asking only for the instrument display reading insufficient?

The displayed number alone does not establish the complete measurement result

What is the first technical challenge?

In 100.12 °C ± 0.15 °C what does 0.15 °C represent?

What is the answer to the technical challenge?

0.15 °C represents the expanded measurement uncertainty

What does the witty challenge ask about a UUT display reading of 100.12 °C?

Whether the display reading can simply be copied to the certificate and why or why not

What VIM references are listed for measurement results?

VIM 3 — JCGM 200:2012 with references 2.9 2.10 and 2.26

What GUM reference is listed?

GUM — JCGM 100:2008 with references 3.1.2 and 7.2

What ISO/IEC reference is listed?

ISO/IEC 17025:2017 Clause 7.8 — Reporting of results

What ILAC reference is listed?

ILAC P14:09/2020

What additional reference is listed?

JCGM GUM-6:2020