| > Both of these are easily biased. Indeed. But remedies exist. Statisticians can examine the validity of the data, analysts and detectives can be trained to interpret the results correctly, and social scientists can point out the dangers of relying solely on computer systems. I have no strong view for or against breathalysers. I'll concede that there may be some errors in those tests. Does that completely invalidate these tools in judging if someone is too drunk to drive and may cause harm to self or others? Should we only opt for rigorous methods like drawing blood samples? My view is: no, we should not. These are valuable tools that work for the large majority of times and help save lives (at the inevitable cost of some errors and inconvenience). In my world I believe in just intentions. Breathalysers are not introduced to imprison sober drivers, they are to combat drunk ("lazy, incompetent or malicious") drivers on our roads. These methods are useful for catching the savvy criminals too. I am not ignoring that these systems are also useful to target activists and political dissidents. That's basically what they were build for in the first place (well, that and the terrorists, see DARPA LifeLog). It's just now that these tools are adopted by local Police departments. A weapon stick can be used to subdue a suspect through non-lethal force, and it can be used to choke a peaceful protester. It will succeed in both tasks. It's not a stupid ineffective tool we should take away, because it can be used in bad ways. We should make sure to avoid the bad usage, and provide police with the best weapon stick possible for the good usage. You assume that this system will be used to justify police brutality and that this system will be used by people who think that any black person is a "criminal". I have a higher opinion of the people who join the police. I rather reserve such judgment to the criminals themselves. |
Yes, when the error is this large and so easily manipulatable. (breathalysers are notorious for being incredibly broad in what the detect (bad false positive rate), and they are required to assume a 2100:1 ratio when estimating blood concentration from the measured breath concentration. In reality, there is a lot (up to +/-800 for some people). There is a good, science-based reason for that ratio involving the partial pressure of EtOH. The reason is valid, it simply ignores the (large) minority of cases where other factors complicate the analysis.
You may suggest that it would be easy to use modern techniques to find a better formula that accounts for these variations. That would work... but it has always been possible. You don't need anything particularly fancy to add a few corrections. These problems - and how to correct them - have been known for decades, yet breathalysers haven't changed. Why? Because an inaccurate tool gives police the leeway to target a much larger set of people (if they want to - selective enforcement is a powerful tool).
> Should we only opt for rigorous methods like drawing blood samples?
Yes, absolutely, and I (and many defence lawyers and civil right organizations) recommend insisting on a blood test should you ever asked to take a breathalyser because of how inaccurate and manipulatable the breath test is in real-world situations. (disclaimer: this can vary between states; see a local lawyer for proper advice)
> at the inevitable cost of some errors and inconvenience
A necessary feature of a free society is the assumption of innocence until proven guilty. Law enforcement is deliberately given a harder task, because errors are not simply an inconvenience. Errors risk charging an innocent person with a crime. You would not call being arrested because of a false-positive an inconvenience.
> You assume that this system will be used to justify police brutality and that this system will be used by people who think that any black person is a "criminal".
I don't need to assume anything. These things are already extremely common today without the need for advanced data processing techniques. If for some reason you doubt these facts, you may want to look up the per-capita incarceration rates by race and compare that to stuff like the drug use rates for the same groups.
> In my world I believe in just intentions
https://en.wikipedia.org/wiki/Just-world_fallacy
> I have a higher opinion of the people who join the police
I prefer to keep my opinions based in reality.
While I'm sure only a minority of police are abusive, the rest are aiding and abetting by not reporting the crimes committed other officers. Misprision of felony is still a crime in the US (18 U.S. Code § 4) ( https://www.law.cornell.edu/uscode/text/18/4 )