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Comment by wolco | Hacker News Reader

It is not that simple. Within the control group of non-smokers you need people who smoked yesterday or 12 hours before to determine if the testing is successful.

But even that is too simplist. You need to activity give a specific dose to a group with similiar profiles. You need to test with different profile groups.

Remember we are testing currently high not has been high.

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The basic functionality of a breathalyzer is to take a given volume of an exhale and measure the concentration of a given particle as an indicator of intoxication. So long as an individual's results are greater than or equal to 0.08 then it becomes an unacceptable risk and they are considered intoxicated. If this process is going to test in a similar way, there is no need to test specific doses or profiles because the concentration isn't variable, it's a static amount. With alcohol, we don't consider weight, or what they had to drink, or how long they've drank so why should this be any different? All that needs to be defined is what the law considers a concentration which should represent a level where the risk reaches an unacceptable percentage.

I think maybe you misunderstood @wolco's point? I think what they are saying is that, for example, you might do all of your testing on college age males and find that it doesn't give any false positives for people who smoked yesterday but not today. But you still need to test it on 60 year old women to make sure it doesn't give false positives there. In other words, you need to test it for varying lengths of time and also to make sure that it has consistently acceptable results by race, sex, weight, age, etc.

Additionally you need to test it doesn't trigger a positive when someone had a cinnamon flavored mint before. Or a citrus one. Or ate a mushroom sandwich. Or has diabetes..etc etc

If that is indeed what they're saying, my point still stands. The blood alcohol limit has no variations for age, sex, gender, race, weight, time since last usage, or any other factor. It just goes by concentration. My point still stands. What the law considers the concentration which indicates intoxication is a metric based on what is considered an acceptable level of risk.

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