
Tesla’s Driver Fatality Rate is more than Triple that of Luxury Cars - cs702
https://medium.com/@MidwesternHedgi/teslas-driver-fatality-rate-is-more-than-triple-that-of-luxury-cars-and-likely-even-higher-433670ddde17
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google_censors
The author of this article claims to have received an award for at least one
published medical study, and I think someone should take a serious look at it.
If he thinks that this methodology is okay in a study, I can't imagine what
would happen if someone used his medical study for anything but laughs.

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tzm
Written by a L/S HF analyst with a current position on TSLA: "Following this
publication, we intend to continue transacting in the securities covered
herein [...]"

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et2o
Is this really what passes for statistical analysis in the investment
community? From a biomedical statistics background, this analysis so atrocious
that I don't know where to start.

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wjnc
So please explain. It's quite a long story but with some good finds (data
quality problems, obfuscated reporting, probability of much higher casualty
rate). I wonder what your statistical rigour makes of this.

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google_censors
Well, including data from China for only Tesla is a joke. That would be like
saying "we couldn't find any deaths from Ebola in the United States, so we
took the ones in Africa and added them in. Wow, look at how many deaths per
year from Ebola occurred in the US compared to deaths from the plague in the
US!". It makes absolutely no sense.

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wjnc
Well it might be. They also include a casualty from NL at face value, while
casualties are MUCH rarer here. I agree with the need for discounting of a
Chinese casualty, but it's quite common practice to try to get more data
points. That is good practice, not bad, and we only seem to disagree with the
execution (is a China casualty 1 or .8?) In this case it wouldn't matter the
base take-away much.

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AstralStorm
You have to at least account for differences in base rate of accidents. The
typical normalisation would take at least published accident total to
synthesise data for the other cars. (By using sales numbers of cars.)

What he did there is statistically unacceptable.

The medical equivalent would be to compare side effect profile of current best
of line treatment done in general populace to results to your new treatment's
phase 1 trial results which is done in healthy people only. Then advertise
that.

Regardless, can we have the raw data please? Are the rates even meaningful
when the incident counts are low? Vehicle years are not the right unit as this
counts cars that are not being driven. Actual range driven is the right unit.

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wjnc
I totally agree. But keep in mind the effect "doing the right thing" has on
the effect to be estimated. I venture it will not change the gist of the
story. Heck, I should contact the author and build a shiny app to demonstrate.
Even discounting a Chinese death 50% would put Tesla in the ballpark double
the risk of luxury cars. My thought would be that Tesla is more a supersport
car (McLaren, etc) in risk (for some drivers, say, male, young or midlife,
etc).

That one local death in NL, the guy did double the allowed speed on a stretch
where I can hardly hit 20% above the allowed speed accounting for traffic
lights and local situation. The one Tesla death with the young kid, the same.
Don't put maximum traction hundreds of HP in male hands. We tend to use it
(sometimes).

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AstralStorm
I suspect the correct use of Chinese data would make error bars overlap,
exposing the BS.

Moreover, they should use the data where miles drive is available, say, from
taxi drivers. Oops, that's 0 out of 0 total? :)

For such low incidences, even studentising will not produce right confidence
intervals based on normal distribution. Poisson distribution cannot even be
used, direct binomial instead, because it is likely that the error due to
approximation will be important. (calculate from rule of rare events)

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dd36
So much FUD.

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arbie
Why? Seems fairly rigorous, with vested interests clearly declared.

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rgbrenner
Rigorous? lol. I'm usually slightly critical of tesla.. but this article is
terrible.

It's so long because the author needs to jump through too many hoops to end up
where he wants to go. Audi A6 has 0 causalities? Cool. Tesla has 0 in one
year? Extremely suspicious. Not enough Tesla accidents in the database?
Include China. Should he include China for the other cars? Nah.

This article is a joke.

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dahdum
The firm is short Tesla, but I’d still like to see a data driven Tesla
rebuttal before believing it’s all smoke and no fire.

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rgbrenner
The data is in the article. They didn't like the conclusion, so then they
included China, did a google search for tesla accidents, and made adjustments
--only to tesla--until they got what they wanted. They aren't even comparing
like with like... all of the conclusions are invalid.

I don't think this article was written in good faith.

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dahdum
They found clear Tesla fatalities that were missing from the published data,
apparently a significant number of them due to miscategorization.

Now maybe all the brands have the same problem with missing data, but that
would mean fatalities across the board are much higher than reported by the
insurance agency funded research firm. That doesn’t seem as likely to me, but
I do believe more research needs to be done.

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ajross
> They found clear Tesla fatalities that were missing from the published data

They _looked_ for Tesla fatalities because they needed more to make the
argument they wanted. You understand the distinction, right?

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dahdum
Yes, they are obviously biased and openly so, but they've raised what appear
to be valid points that Tesla should answer. Elon made the claim publicly, and
Tesla is no stranger to writing snatching rebuttals.

As disclosure, I'm long TSLA, both index and individual shares.

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cs702
I submitted the OP, and am a bit surprised to see it flagged. The OP looks to
me like a sincere attempt to analyze fatality data.

Yes, the authors are short Tesla, but they disclose it. Yes, the analysis is
naive, but that doesn't necessarily mean its conclusions are off. Yes, the
inclusion of data from China is... questionable, but the authors address it
upfront: _" To have the largest sample size and best confidence intervals
possible, we also included international accidents (three total, from Canada,
Holland, and China). Given the higher incidence of fatal accidents per
vehicle-year in China compared to the United States, and the lower incidence
of fatal accidents in Holland and Canada, these three deaths should adjust to
3.63 deaths. However, for the sake of conservatism and to avoid a large debate
about a rather small difference, we use 3.00 deaths in our analysis."_

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dahdum
Doesn't deserve the flag IMO, Tesla is an emotional topic for many people.
While there certainly have been hit pieces and hack journalism throughout the
companies existence, I think this one has enough meat to be worth discussing.

Like most investors, I'm long TSLA. Both index and individual shares.

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cs702
Yes, exactly my thoughts.

I would have liked to see the HN community rationally debate what to me looks
like an earnest but naive analysis of fatality rates -- based on its merits or
lack thereof. Instead, at least some in the HN community have resorted to _ad
hominem_ attacks ("Tesla short!") and flagging.

For the record, I'm a _huge fan_ of Musk and the company, but other than
minimal long exposure through passive funds, I have no position in Tesla.

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exabrial
Why do these keep getting submitted to hn? Ffs

