We got drunk at work to find out how easy it is to guess a person's level of intoxication based only on their behavior.
(Important: Nobody who participated in this drove home drunk! Never drive when you have been drinking!)
The scientific way to figure out a person's shwasteyness is to measure their blood alcohol content (BAC).
BAC is the percentage of ethanol in your blood in units of mass of alcohol per volume (or mass) of blood. Cops and doctors can measure this with a breathalyzer.