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Car alarms and smoke alarms: tradeoff between sensitivity and specificity (2012)

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Re: Car alarms and smoke alarms: tradeoff between sensitivity and specificity (2012)

#71

Post by mjevans »

tobyjsullivan wrote: post #25
dfox wrote: post #21

Smoke(/fire in general) alarms are not a good example of a thing with high specificity. You perceive it that way, but what you see is the result of somebody getting paged about it and then checking (preferably physically, but also through eg. CCTV) whether there really is an emergency situation and canceling the alarm before its escalation timeout. Apparently, for typical commercial building false fire alarms are mor…

It was an interesting example and maybe deserved a few more caveats to actually serve the point. After all, we've all heard a fire alarm of some sort in the past year (if not the past month) but how many were actual fires? (Technically the author said smoke which helps but not really.) Where I was expecting the author to go: - Clearly was talking about residential smoke detectors, not commercial. That could have been…

I have been _plagued_ by smoke alarms that treat a low battery as a sign of a fire. To the point that I am trained by their crying wolf that it is _always_ a false alarm. Particularly when I'm asleep and they've gone off.

I would actually prefer if rules mandated they could only have large capacitors and just NOT CARE if the power goes out.

Next would be to require a sensor pick up an area that's IR hot AND smoke to go off. I'm sick of bathroom steam sometimes setting them off too.

Finally, ONLY FOR EMERGENCY would the loud and annoying cry be allowed. Tests, low battery, anything not indicating a clear and immediate threat to life should be a low noise, low light, indication. Maybe a 2 second low-quality sound clip that says 'bat' at a soft voice volume with a strobe at the end of the voice (when a human would be looking for the noise). Fog/Steam/etc, E.G. possible fire without detected heat but at a weak detection level, could also use the 'info' level of alert, not the DANGER level.

Re: Car alarms and smoke alarms: tradeoff between sensitivity and specificity (2012)

#72

Post by swexbe »

hackernewds wrote: post #69
eatsyourtacos wrote: post #58

Earlier quoted context omitted.

>Many insurance companies offer lower premiums if you install a car alarm. So I guess they work at least a little, otherwise they wouldn't lower their premiums. I can think of another reason. They run their computations- and say the insurance can be priced at $100. But hey what if we just increase to $105, and then offer a $5 discount to people who have car alarms? We get extra money (average of >100) and people thin…

if you believe insurance companies have miscalculated their risk models, perhaps there is a massive business opportunity to undercut them then.

Only for the not so lucrative market of car owners without car alarms. Since all new cars are outfitted with one I would guess this would be the n% least willing to spend on their cars.

Re: Car alarms and smoke alarms: tradeoff between sensitivity and specificity (2012)

#73

Post by lostlogin »

hackernewds wrote: post #69
eatsyourtacos wrote: post #58

Earlier quoted context omitted.

>Many insurance companies offer lower premiums if you install a car alarm. So I guess they work at least a little, otherwise they wouldn't lower their premiums. I can think of another reason. They run their computations- and say the insurance can be priced at $100. But hey what if we just increase to $105, and then offer a $5 discount to people who have car alarms? We get extra money (average of >100) and people thin…

if you believe insurance companies have miscalculated their risk models, perhaps there is a massive business opportunity to undercut them then.

A better business case:

Insurance: $105, with alarm: $100

‘And here is a discount code for use with company X’.

And every referral get a kickback. Profit.

Re: Car alarms and smoke alarms: tradeoff between sensitivity and specificity (2012)

#74

Post by lostlogin »

mjevans wrote: post #71
tobyjsullivan wrote: post #25

Earlier quoted context omitted.

It was an interesting example and maybe deserved a few more caveats to actually serve the point. After all, we've all heard a fire alarm of some sort in the past year (if not the past month) but how many were actual fires? (Technically the author said smoke which helps but not really.) Where I was expecting the author to go: - Clearly was talking about residential smoke detectors, not commercial. That could have been…

I have been _plagued_ by smoke alarms that treat a low battery as a sign of a fire. To the point that I am trained by their crying wolf that it is _always_ a false alarm. Particularly when I'm asleep and they've gone off. I would actually prefer if rules mandated they could only have large capacitors and just NOT CARE if the power goes out. Next would be to require a sensor pick up an area that's IR hot AND smoke to…

I’m at the point where a low battery in a smoke detector triggering a fire would be an actual upgrade. Have tried cheap, expensive, and multiple models. Currently have zero active and about 8 on a shelf. They randomly go off even with new batteries. My house isn’t on fire.

Re: Car alarms and smoke alarms: tradeoff between sensitivity and specificity (2012)

#75

Post by eutectic »

GuB-42 wrote: post #43
sammalloy wrote: post #23

The entire car alarm industry is a scam, promoted by Republican congressman Darrell Issa. It has seriously disrupted our lives in every way imaginable and has drowned out the beauty of nature. I can’t think of a single car that has been protected by a car alarm since they were invented. They are useless and should be banned for the health and safety of mitigating noise pollution.

> I can’t think of a single car that has been protected by a car alarm since they were invented. Many insurance companies offer lower premiums if you install a car alarm. So I guess they work at least a little, otherwise they wouldn't lower their premiums. It may not actually stop a thief, but it may get a thief to chose a car that doesn't have an alarm, or maybe it is just a correlation, but there is at least someth…

If you change the requirements for an insurance policy you attract a different risk pool. Just like health insurance companies offering gym membership to find healthier customers.

Re: Car alarms and smoke alarms: tradeoff between sensitivity and specificity (2012)

#76

Post by blep_ »

lostlogin wrote: post #74
mjevans wrote: post #71

Earlier quoted context omitted.

I have been _plagued_ by smoke alarms that treat a low battery as a sign of a fire. To the point that I am trained by their crying wolf that it is _always_ a false alarm. Particularly when I'm asleep and they've gone off. I would actually prefer if rules mandated they could only have large capacitors and just NOT CARE if the power goes out. Next would be to require a sensor pick up an area that's IR hot AND smoke to…

I’m at the point where a low battery in a smoke detector triggering a fire would be an actual upgrade. Have tried cheap, expensive, and multiple models. Currently have zero active and about 8 on a shelf. They randomly go off even with new batteries. My house isn’t on fire.

I have literally never had this problem.

I don't mean that in a "so you must be wrong" way, but "there may be something up with your situation besides the smoke alarms themselves".

Re: Car alarms and smoke alarms: tradeoff between sensitivity and specificity (2012)

#77

Post by kloch »

sammalloy wrote: post #23

The entire car alarm industry is a scam, promoted by Republican congressman Darrell Issa. It has seriously disrupted our lives in every way imaginable and has drowned out the beauty of nature. I can’t think of a single car that has been protected by a car alarm since they were invented. They are useless and should be banned for the health and safety of mitigating noise pollution.

This was true in the early 1990's but I rarely hear a car alarm these days.

There was one particularly annoying car alarm that was popular in the 1990's that had a sequence of "police/ambulance siren" sounds.

Bieww Bieww Bieww Bieww, oooo eeee oooo eeee, rrr rrr rrr rrr, ee oo ee oo, booooooooup booooooooup booooooooup booooooooup, oooooooo eeeeeeee oooooooo eeeeeeee

Or something like that.

Re: Car alarms and smoke alarms: tradeoff between sensitivity and specificity (2012)

#78

Post by mjevans »

blep_ wrote: post #76
lostlogin wrote: post #74

Earlier quoted context omitted.

I’m at the point where a low battery in a smoke detector triggering a fire would be an actual upgrade. Have tried cheap, expensive, and multiple models. Currently have zero active and about 8 on a shelf. They randomly go off even with new batteries. My house isn’t on fire.

I have literally never had this problem. I don't mean that in a "so you must be wrong" way, but "there may be something up with your situation besides the smoke alarms themselves".

My guess is the landlord's invariably choose the cheapest models that check the box; or that everything out there just sucks for some reason.

Re: Car alarms and smoke alarms: tradeoff between sensitivity and specificity (2012)

#79

Post by okdood64 »

raldi wrote: post #8

When the oncall gets paged, an SLO should be in jeopardy in a way that requires immediate measures to be taken by a well-trained human as described in actionable terms in a linked playbook. No SLO in jeopardy, or no immediate measure that needs to be taken? Don't page the oncall; send a low-priority ticket for the service owner to investigate the next business day. Steps need to be taken, but they're mechanical in na…

> When the oncall gets paged, an SLO should be in jeopardy in a way that requires immediate measures

> No SLO in jeopardy, or no immediate measure that needs to be taken?

A little contradictory here. Maybe your "or" should've been an "and". But anyways:

I can think of several scenarios for which an SLO is not in jeopardy for which you should get paged. All of which boils down to "Yes it is important for the business, our users, our brand" but still not worth having an SLO around because it's either 1) hard to measure or 2) too difficult to implement.

In an ideal world with infinite engineering resources on your team, you could have and _maintain_ an SLO for every part of the business that your system effects. In the real world, trade-offs need to made and certain key SLOs prioritized.

Re: Car alarms and smoke alarms: tradeoff between sensitivity and specificity (2012)

#80

Post by lostlogin »

blep_ wrote: post #76
lostlogin wrote: post #74

Earlier quoted context omitted.

I’m at the point where a low battery in a smoke detector triggering a fire would be an actual upgrade. Have tried cheap, expensive, and multiple models. Currently have zero active and about 8 on a shelf. They randomly go off even with new batteries. My house isn’t on fire.

I have literally never had this problem. I don't mean that in a "so you must be wrong" way, but "there may be something up with your situation besides the smoke alarms themselves".

> there may be something up with your situation besides the smoke alarms themselves

Completely agree and it’s very frustrating. My guess is humidity, as hot nights seem to be when they go off.

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