44 ms·

Statistics Blunder at the Supreme Court

23 points by Tomte 2y ago

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dmbche 2y ago
I must be thick skulled, but doesn't this paragrqph from the article provide the evidence they claim they don't have? "As far as I can tell, the justification for the quote is probably in Table 1, col. 1. Baseline mortality rate (white newborn + white dr) is 290 (per 100k). Black newborn is +604 above that giving 894/100k. Then -494 from that when it is black newborn + black dr giving 400/100k. So the black newborn mortality rate is more than cut in half when the doctor is also black." What am I missing?
- zelos 2y ago
  If I'm understanding correctly, the issue is "twice as likely to live" vs "half as likely to die", which isn't quite as terrible a mistake as the intro makes out IMHO.
  - dmbche 2y ago
    I think you're right - thanks!
  - pbhjpbhj 2y ago
    Except 0.07% (99.87/99.8) more likely to live when cared for by a black doctor is quite different to "twice as likely". Still deserves investigation, hundreds of babies died, but it's a very different statistic.
- spywaregorilla 2y ago
  Halving the probability that a baby dies isn't the same thing as doubling the probability that the baby lives.
jmull 2y ago
> Indeed, there’s no treatment that will take the survival rate up to 198%. It seems willfully obtuse to read the language in the ruling that way.
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jp57 2y ago
Isn't this just a mixup in terminology and the meaning of "likelihood"? It seems from the article that odds of survival approximately double in the cited data. EDIT: I run into this same mixup in other contexts. Gompertz's law on mortality is often described as "the likelihood of mortality" or "the mortality rate" doubling every eight years, both of which are impossible once likelihood and/or rate are above 0.5. But odds can keep doubling indefinitely.
- defen 2y ago
  > It seems from the article that odds of survival approximately double in the cited data. What are the actual numbers for the 2 different odds of survival you're comparing here?
  - jp57 2y ago
    From the article: As far as I can tell, the justification for the quote is probably in Table 1, col. 1. Baseline mortality rate (white newborn + white dr) is 290 (per 100k). Black newborn is +604 above that giving 894/100k. Then -494 from that when it is black newborn + black dr giving 400/100k. So the black newborn mortality rate is more than cut in half when the doctor is also black. Black newborn survival rate 894/100k. Survival odds = (100k-894)/894, or about 111-to-1. Black newborn + black dr survival rate 400/100k. Survival odds (100k-400)/400, or about 249-to-1.
pbhjpbhj 2y ago
Precis: Mortality went from 0.13% to 0.2% for newborn black babies with a black doctor presiding (no effect found based on skin colour of obstetrician), in a longitudinal study in Florida. This was erroneously declared as black babies having double the chance of living if they had a black doctor. By my maths the actual increase is 0.07% (99.87/99.8). The conclusion drawn was that white doctors provide [far far] worse care to black babies.
- antisthenes 2y ago
  > Mortality went from 0.13% to 0.2% for newborn black babies with a black doctor presiding (no effect found based on skin colour of obstetrician), in a longitudinal study in Florida. If Mortality increased, that means less babies survive. The chance of living is thus reduced, by definition. It can't be double anything.

23 points by Tomte 2y ago

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dmbche 2y ago

I must be thick skulled, but doesn't this paragrqph from the article provide the evidence they claim they don't have? "As far as I can tell, the justification for the quote is probably in Table 1, col. 1. Baseline mortality rate (white newborn + white dr) is 290 (per 100k). Black newborn is +604 above that giving 894/100k. Then -494 from that when it is black newborn + black dr giving 400/100k. So the black newborn mortality rate is more than cut in half when the doctor is also black." What am I missing?

zelos 2y ago
If I'm understanding correctly, the issue is "twice as likely to live" vs "half as likely to die", which isn't quite as terrible a mistake as the intro makes out IMHO.
- dmbche 2y ago
  I think you're right - thanks!
- pbhjpbhj 2y ago
  Except 0.07% (99.87/99.8) more likely to live when cared for by a black doctor is quite different to "twice as likely". Still deserves investigation, hundreds of babies died, but it's a very different statistic.
spywaregorilla 2y ago
Halving the probability that a baby dies isn't the same thing as doubling the probability that the baby lives.

jmull 2y ago

> Indeed, there’s no treatment that will take the survival rate up to 198%. It seems willfully obtuse to read the language in the ruling that way.

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jp57 2y ago

Isn't this just a mixup in terminology and the meaning of "likelihood"? It seems from the article that odds of survival approximately double in the cited data. EDIT: I run into this same mixup in other contexts. Gompertz's law on mortality is often described as "the likelihood of mortality" or "the mortality rate" doubling every eight years, both of which are impossible once likelihood and/or rate are above 0.5. But odds can keep doubling indefinitely.

defen 2y ago
> It seems from the article that odds of survival approximately double in the cited data. What are the actual numbers for the 2 different odds of survival you're comparing here?
- jp57 2y ago
  From the article: As far as I can tell, the justification for the quote is probably in Table 1, col. 1. Baseline mortality rate (white newborn + white dr) is 290 (per 100k). Black newborn is +604 above that giving 894/100k. Then -494 from that when it is black newborn + black dr giving 400/100k. So the black newborn mortality rate is more than cut in half when the doctor is also black. Black newborn survival rate 894/100k. Survival odds = (100k-894)/894, or about 111-to-1. Black newborn + black dr survival rate 400/100k. Survival odds (100k-400)/400, or about 249-to-1.

pbhjpbhj 2y ago

Precis: Mortality went from 0.13% to 0.2% for newborn black babies with a black doctor presiding (no effect found based on skin colour of obstetrician), in a longitudinal study in Florida. This was erroneously declared as black babies having double the chance of living if they had a black doctor. By my maths the actual increase is 0.07% (99.87/99.8). The conclusion drawn was that white doctors provide [far far] worse care to black babies.

antisthenes 2y ago
> Mortality went from 0.13% to 0.2% for newborn black babies with a black doctor presiding (no effect found based on skin colour of obstetrician), in a longitudinal study in Florida. If Mortality increased, that means less babies survive. The chance of living is thus reduced, by definition. It can't be double anything.