Metrology is the science
A person who performs measurements may be a metrologist or calibration technician.
So how do you know if your yardstick is really a yard long? Do you really believe that thermometer stuck in your ... mouth? 6 inches? Sounds of female laughter....
You're going to need to learn you some metrology, dude. Teach you some ways to make measurements using traceable standards. Figure out parameters and uncertainties. Lots of cool equipment with blinking lights!
Common measurement parameters include temperature, pressure, mass, length, voltage, current, resistance, capacitance, inductance, frequency, and power.