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A Way to Detect Bias

paulgraham.com

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Re: A Way to Detect Bias

#41

Post by yummyfajitas »

MattHeard wrote: post #37
yummyfajitas wrote: post #33

People, most of whom clearly are not that good at math, are being really harsh on Paul Graham. Graham is mostly right, but slightly incorrect. In particular, suppose group A has the distribution f(x) and B has the distribution g(x). If f(x) and g(x) are shaped significantly differently past the cutoff , then mean(H(x-C)f(x)) and mean(H(x-c)g(x)) might not agree even though there is no bias by construction. (Here H(x)…

Wouldn't the weakest male and weakest female founders be underperforming more due to individual factors than bias? Maybe a mean of the lower quartile would remove some the the noise.

Suppose the cutoff for men is C but for women is C+K. Then the weakest man can be expected to have quality C+epsilon, while the weakest woman will have quality C+K+epsilon.

Here epsilon is how close a typical candidate will be to the cutoff, and is mainly a function of the sample size. I don't know the behavior of epsilon off the top of my head.

Re: A Way to Detect Bias

#42

Post by suchow »

WildUtah wrote: post #20

On a simple mathematical basis, this is false. Consider two groups of candidates for a scholarship, A and B. We want to select all candidates that have an 80% or better chance of graduation. Group A comes from a population where the chance of graduation is distributed uniformly from 0% to 100% and group B is from one where the chance is distributed uniformly from 10% to 90%, with the same average but less variation i…

This logic is similar to that of Larry Summers in his remarks about diversity in science and engineering, http://www.harvard.edu/president/speeches/summers_2005/nber.....

Re: A Way to Detect Bias

#43

Post by rewqfdsa »

WildUtah wrote: post #20

On a simple mathematical basis, this is false. Consider two groups of candidates for a scholarship, A and B. We want to select all candidates that have an 80% or better chance of graduation. Group A comes from a population where the chance of graduation is distributed uniformly from 0% to 100% and group B is from one where the chance is distributed uniformly from 10% to 90%, with the same average but less variation i…

Why are you using biased mathematics? If statistics and the scientific method (the tools through which dead white men continue to colonize) give us obviously problematic results, we should abandon them in favor of a method of inquiry that promotes social justice.

Re: A Way to Detect Bias

#44

Post by earljwagner »

yummyfajitas wrote: post #35
earljwagner wrote: post #32

The phenomena of "stereotype threat" complicates this conclusion however: https://en.wikipedia.org/wiki/Stereotype_threat When a member of a group is primed with a stereotype that their group underperforms at a task, they are more likely to underperform. So there could be a selection process biased against a group, and a selected member could be an above-average performer otherwise but, because of work environment, b…

This is only a bias if the stereotype effect is stronger on measurements than in real life. If stereotype threat affects test performance and real performance the same way, then it means that the stereotyped group is truly inferior. Do you have evidence that stereotype threat hurts test performance more than real performance? (Of course, in a hypothetical world which only eliminated the stereotype, the group would ce…

I wouldn't agree with the conclusion of being truly inferior - there could be ongoing issues with the work context.

I'll put it another way: Graham says we can look at just the performance by group to detect bias in selection. But there could be bias in selection, and A) different treatment after selection, which would not be revealed through Graham's test. Or could also be bias in selection and B) continuous reminders of stereotypes triggering stereotype threat, and this would also not be revealed.

Now you could point to a tech company with few underrepresented minorities, let's say 1%. If there's no overt bias in the work environment then people should succeed and if they don't they're just worse performers. On the other hand, if you're in the 1%, just noticing the underrepresentation among your coworkers might be a constant reminder of stereotypes.

I don't claim to have a simple solution for this.

Re: A Way to Detect Bias

#45

Post by robot22 »

WildUtah wrote: post #20

On a simple mathematical basis, this is false. Consider two groups of candidates for a scholarship, A and B. We want to select all candidates that have an 80% or better chance of graduation. Group A comes from a population where the chance of graduation is distributed uniformly from 0% to 100% and group B is from one where the chance is distributed uniformly from 10% to 90%, with the same average but less variation i…

I find it slightly amazing he posted this. Did he not bother to ask someone with a probabilistic background before posting?

Re: A Way to Detect Bias

#46

Post by gizmo »

cookiecaper wrote: post #31
gizmo wrote: post #7

A related observation (which I've been making for a long time) is that the absence of mediocre women in positions of power is strong evidence of bias. Men can succeed when they're mediocre, but women have to be exceptional. Likewise for minorities.

What's "exceptional"? I've known many women in my career and many of them were mediocre. Some were in positions of authority and some weren't. Another commenter lists several "mediocre" women in the corporate and political world (and leaves out some big ones, like Meg Whitman). If you're talking about becoming a CEO, you have to be an "exceptional" man to get there too, in absolute terms. I feel like the root erroneo…

> People make decisions based on social, cultural, and physical expectations of them, and there's not anything wrong with that.

I couldn't disagree more. If the culture is plain chauvinism ("women belong in the kitchen not the boardroom") then there's everything wrong with that. All oppression throughout history is essentially "just culture", but that justifies nothing.

Your biological reductionism is completely at odds with our best scientific understanding of contemporary gender roles, as a few minutes on wikipedia will tell you.

Re: A Way to Detect Bias

#47

Post by yummyfajitas »

earljwagner wrote: post #44
yummyfajitas wrote: post #35

Earlier quoted context omitted.

This is only a bias if the stereotype effect is stronger on measurements than in real life. If stereotype threat affects test performance and real performance the same way, then it means that the stereotyped group is truly inferior. Do you have evidence that stereotype threat hurts test performance more than real performance? (Of course, in a hypothetical world which only eliminated the stereotype, the group would ce…

I wouldn't agree with the conclusion of being truly inferior - there could be ongoing issues with the work context. I'll put it another way: Graham says we can look at just the performance by group to detect bias in selection. But there could be bias in selection, and A) different treatment after selection, which would not be revealed through Graham's test. Or could also be bias in selection and B) continuous reminde…

Differential treatment after selection would indeed invalidate Graham's test.

Stereotype threat, however, is NOT such a different treatment. Again - if stereotype threat reduces measured performance by X and actual performance by Y, then the bias it introduces is Y-X. If Y=X then there is no bias.

Do you believe Y != X? If so, why?

Re: A Way to Detect Bias

#48

Post by jblow »

All other arguments aside ... this idea also fails if the judging party's idea of quality is mostly uncorrelated with actual quality. Which Graham says in other essays is usually the case (it's what you mean when you say it's almost impossible to predict which companies will be successful).

Graham says the subjects of bias "have to be better to get selected", but what is really going on is they have to be better according to the metrics of the judge which are essentially arbitrary.

Re: A Way to Detect Bias

#49

Post by yummyfajitas »

WildUtah wrote: post #20

On a simple mathematical basis, this is false. Consider two groups of candidates for a scholarship, A and B. We want to select all candidates that have an 80% or better chance of graduation. Group A comes from a population where the chance of graduation is distributed uniformly from 0% to 100% and group B is from one where the chance is distributed uniformly from 10% to 90%, with the same average but less variation i…

Graham's intuition is assuming equality of the two distributions.

As I noted in a different comment here, you can pretty easily fix Graham's test. Compute min(accepted a) and min(accepted B) instead of the means. In your example, the min of the accepted distributions would both work out to be 80%.

Re: A Way to Detect Bias

#50

Post by yummyfajitas »

jblow wrote: post #48

All other arguments aside ... this idea also fails if the judging party's idea of quality is mostly uncorrelated with actual quality. Which Graham says in other essays is usually the case (it's what you mean when you say it's almost impossible to predict which companies will be successful). Graham says the subjects of bias "have to be better to get selected", but what is really going on is they have to be better acco…

This is false - noise doesn't hurt this test at all. See my comment explaining why:

https://news.ycombinator.com/item?id=10483991

Bad measurements add noise (and increase the sample size required) but they don't invalidate the bias detection procedure.

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