6 ms·
This set of trade-offs in self driving cars is exactly the same one that CAD (computer aided detection/diagnosis) systems have been making in medicine for decad
by ska 8y ago
This set of trade-offs in self driving cars is exactly the same one that CAD (computer aided detection/diagnosis) systems have been making in medicine for decades. In many cases both type I and type II errors will (with statistical certainty) kill people over enough iterations.
It's not an easy problem, but the best you can do is demonstrate that the system improves on the standard of care. In other words, overall the trade-off has better outcomes than not using the system. The same will be true for self driving cars if/when they reach mainstream use. The important thing is the average performance is improved significantly.
It's worth noting that, like the CAD systems, focusing too much on fixing an individual error can cause a degradation to the overall system. As these things get better and better, you'll have to be much more careful about applying non-obvious fixes, or risk a much worse outcome that doing nothing at all.
- rayiner 8y agoImagine a CAD system that was so fundamentally unreliable that it ignored positive hits because the high rate of false positives otherwise would make the system useless. Instead, the CAD system came with a warning printed on the instruction manual that a doctor had to review every scan anyway.
- bsder 8y agoWelcome to breast cancer screening. The current systems are so good at detecting tiny anomalies that probably don't matter that their usage has had to be tuned down.
- deleted 8y ago[deleted]
- ska 8y agoYou have to be very careful with false positive rates with something like breast screening, as the work up rate has definite negative consequences. Radiologists have too high a false negative rate on such screens, so you're trying to achieve a balance. To be really blunt about it, you are trading off complications/deaths from missed cancers against complications/deaths from biopsies, but these categories occur at very different rates.
- ska 8y agoIn the US anyway, doctor review is standard-of-care anyway for most of these things. Not necessarily for performance or technical reasons (although it may be) but for liability. I suppose if you know this is the case, you may tune differently on your ROC curve based on joint performance, although I don't know personally of a system that does that explicitly. It isn't really interesting to talk about performance (what I think you mean by "unreliable") in some absolute sense - it's interesting compared to current performance only. So - sure, if the automatic driving systems are significantly enough below human performance in general it's premature to use them on public roads. However, if they are approaching human performance (again, in general), they aren't. And you may see specific new failure modes coming up because of that, but focusing on those modes in isolation is a mistake. I have no knowledge of where the overall performance is for self-driving cars, and hence no opinion as to whether or not we are being premature. I'm just pointing out that the trade off is fundamental, and will effectively never go away regardless of improvements in classifiers.
- joe_the_user 8y agoIf you had a CAD system that could not only diagnose but take immediate action (though surgery or otherwise). If on occasion, this system took actions that would appear to a human being as "completely illogical" and those actions killed people, it would be hard to explain to a person's family or to a jury that "this reduces fatalities on average", even if a company had nice charts that claimed to show this. That's sort of the problem one has in explaining self-driving cars, along with the problem that it hasn't yet been shown they are capable of reducing fatalities.
- ska 8y agoit would be hard to explain to a person's family or to a jury that "this reduces fatalities on average" Yes, that's true. However it is a problem that has to be solved if you want the best outcomes. Anything else will be effectively making things worse for people in general. This isn't a new problem at all, the saying "hard cases make bad law" encodes a similar sentiment from an area with far less empirical outputs.
- petre 8y agoJust beep for every positive, false or otherwise, before braking if no action is taken by the human operator. Also blink the stop light so the operator of the car in the back sees it and gets ready to take acton.
- tempestn 8y agoSo an object is detected, it beeps and flashes the brake lights, then if the driver does nothing, it brakes? What does the driver need to do to have it not brake? What about when there isn't sufficient time between object detection and anticipated impact to warn the driver? What frequency of beeping would be preferable to just driving the car manually?
- petre 8y agoYes, it brakes if the driver does nothing. Preferably slowly if the distance to obstacle allows it. If the user brakes instead, the human operator takes over, even if s/he softly brakes for n seconds, it could turn off the hazard warning. If there isn't sufficient time to warn the driver, have it just brake automatically to avoid collision. This is what AEBS/AEB collision avoidance systems do. Frequency of beeping could be increasing with distance to object, just like parking sensors. Continuous beep = accident imminent.
- ggg9990 8y agoThe standards for self-driving cars are MUCH higher than for computer aided diagnosis. Choice of medical tools is made by trained, rational doctors largely hidden from the public. Self driving cars’ failures will play out in front of normal people who often have emotion-driven subrational decisionmaking processes.
- aggie 8y agoYour point about public visibility stands, but there's plenty of evidence that doctors are irrational just like the rest of us.
- ska 8y agoI'm not claiming they are identical problems. Just pointing out that the fundamental type I/type II trade-offs for the classification part of this are just that - fundamental and unavoidable. The analysis of performance itself is by nature very similar. At least, if you do it properly. How you communicate that data and to who is different, I agree.
- emodendroket 8y agoHard to believe these emotion-driven, subrational people with beliefs like "autonomous cars should not be on the road with the braking features off because the ride is too choppy."
- Waterluvian 8y agoI don't agree that that's the discussion. The discussion is the knob that ranges from "inconvenient" to "occasionally deadly" Imagine being dead because drivers were tired of their overly cautious vehicles.