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A Way to Detect Bias

paulgraham.com

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Re: A Way to Detect Bias

#181

Post by graycat »

pg wrote: post #91
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…

It's true that this test assumes groups of applicants are roughly equal in (distribution of) ability. That is the default assumption in most conversations I've been involved in about bias, and particularly the example I used, but I'll add something making that explicit.

No in the null hypothesis, for the distribution, don't have to care, can be distribution free, except assume that the expected values on the measurements are the same. For details, see my post

https://news.ycombinator.com/item?id=10484602

Re: A Way to Detect Bias

#182

Post by graycat »

pg wrote: post #91
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…

It's true that this test assumes groups of applicants are roughly equal in (distribution of) ability. That is the default assumption in most conversations I've been involved in about bias, and particularly the example I used, but I'll add something making that explicit.

No, in the null hypothesis, for the distribution, don't have to care; the distributions of the measurements for the men and the women can be different; the work can be distribution free, except assume that the expected values on the measurements are the same for the men and women.

For details, see my post

https://news.ycombinator.com/item?id=10484602

Re: A Way to Detect Bias

#183

Post by graycat »

gleb wrote: post #122
pg wrote: post #91

Earlier quoted context omitted.

It's true that this test assumes groups of applicants are roughly equal in (distribution of) ability. That is the default assumption in most conversations I've been involved in about bias, and particularly the example I used, but I'll add something making that explicit.

I like the idea, but how do you apply this to power law distribution outcomes and get any statistical significance? I don't know the answer. E.g. the underlying First Round's analysis likely has no statistical significance. Assuming the power law distribution of outcomes top 5 outcomes will account for 97% of value. So we now have a study with n=5. To make the point let's apply this to YC's own portfolio. Assuming Dr…

> I like the idea, but how do you apply this to power law distribution outcomes and get any statistical significance? I don't know the answer.

See my post

https://news.ycombinator.com/item?id=10484602

where are distribution-free. So "power law", Gaussian, anything else, doesn't matter.

Re: A Way to Detect Bias

#184

Post by WildUtah »

rewqfdsa wrote: post #176
gammarator wrote: post #172

Earlier quoted context omitted.

> you're essentially postulating a giant unconscious conspiracy Let me introduce you to the extensive scientific literature on implicit bias: http://www.aas.org/cswa/unconsciousbias.html

If the bias reflects a real Bayesian prior, it isn't the kind of bias that's unjust.

So if Americans from race A commit ten times more violent crime than others and the police consequently accuse and manhandle vast numbers of innocent Americans of race A, there's nothing unjust about that? The vast majority of citizens of race A are innocent of all offenses but deserve constant suspicion and low level official humiliation and violence in a just world for no reason other than being the same color as some crooks.

I don't agree.

Re: A Way to Detect Bias

#185

Post by igonvalue »

pg wrote: post #91
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…

It's true that this test assumes groups of applicants are roughly equal in (distribution of) ability. That is the default assumption in most conversations I've been involved in about bias, and particularly the example I used, but I'll add something making that explicit.

Assuming that the distributions are exactly equal, the test would still give misleading results in situations in which the bias does not manifest as a different cutoff.

For example, if a VC funds all male founders but flips a coin to decide whether to fund each female founder, the test would fail to detect overwhelming bias.

Obviously that specific scenario is not realistic, but I believe something like this is plausible enough: A VC funds all male founders who are considered promising, and all female founders who are considered promising AND went to school with one of the partners.

And it's not hard to imagine a plausible scenario in which the test would give false positives rather than false negatives.

Re: A Way to Detect Bias

#186

Post by graycat »

rewqfdsa wrote: post #43
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.

> social justice

Gee, I never saw a definition. Not sure the meaning of the phrase is clear without a definition.

Re: A Way to Detect Bias

#187

Post by WildUtah »

drumdance wrote: post #171
rewqfdsa wrote: post #130

Earlier quoted context omitted.

Which is more plausible? a) the action of natural selection, sexual selection, and the hormone environment magically stop at the blood-brain barrier, or b) there are real group differences between human populations? We've already eliminated all overt discrimination. If you continue to cry discrimination, you're essentially postulating a giant unconscious conspiracy. I find the idea wildly implausible. It's much simpl…

Women musicians started getting orchestra positions in much greater numbers after auditions were made blind. If biases affect how a professional musician hears music, is it so shocking to think unconscious bias might affect someone's judgment a candidate based on multiple fuzzy factors like ability, culture, and personality? And that's just for job applications. You really think the criminal justice system has remove…

Criminal justice and orchestra employment are non-market phenomena. The people in charge do not benefit if the orchestra is great and are not accountable if innocents go to jail and murders spree freely and the tubas clank.

So of course the bosses pick out their friends and cronies. And a decent polity should restrain their corruption with blind auditions and accountable audits of prosecutions.

But investors should be looking for a good return on their money. They should be looking for the best investments they can find. If they're not, that is the source of bias right there.

Of course, the Wall Street industry is located in New York because you can use big city lights, strippers, and steaks to scam small town municipal pension fund managers who aren't investing their own money. Sand Hill Road is supposed to operate on different principles.

Re: A Way to Detect Bias

#188

Post by [deleted] »

gleb wrote: post #122
pg wrote: post #91

Earlier quoted context omitted.

It's true that this test assumes groups of applicants are roughly equal in (distribution of) ability. That is the default assumption in most conversations I've been involved in about bias, and particularly the example I used, but I'll add something making that explicit.

I like the idea, but how do you apply this to power law distribution outcomes and get any statistical significance? I don't know the answer. E.g. the underlying First Round's analysis likely has no statistical significance. Assuming the power law distribution of outcomes top 5 outcomes will account for 97% of value. So we now have a study with n=5. To make the point let's apply this to YC's own portfolio. Assuming Dr…

[deleted]

Re: A Way to Detect Bias

#189

Post by T2_t2 »

pg wrote: post #91
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…

It's true that this test assumes groups of applicants are roughly equal in (distribution of) ability. That is the default assumption in most conversations I've been involved in about bias, and particularly the example I used, but I'll add something making that explicit.

Correlation != causation, and even if the correlation reveals something, with no explanatory theory, we are still at step one.

This essay was based on these two lines from here: http://10years.firstround.com/#one

> That’s why were so excited to learn that our investments in companies with at least one female founder were meaningfully outperforming our investments in all-male teams. Indeed, companies with a female founder performed 63% better than our investments with all-male founding teams

The comparison is not clear, but is not women versus men, but between companies with X number of males plus at least one female founder, versus those with zero female founders and Y male founders.

If we skip a step and take this fact as having some predictive value, it could be lots of things, including off-the-top-of-my-head:

1. Bias against women - which extends to teams that include men, e.g. the bias against woman exists in the presence of male co-founders.

2. That the personality traits shared by groups where women co-found startups with men are positively correlated with success. It is quite possible that these groups have much better EQ, while still retaining the IQ to impress the required amount to be selected.

3. That startups with at least one female select, and I am using this term in a very stereotyped way, "not-white-male" startups. Many Unicorn startups, from Atlasssian to Dropbox, specialise in problems faced by, again for wont of a better term, "white males". Given the mantra of solving problems we have ourselves, it is possible that mixed groups choose less male subjects. As men have been the founders of the majority of startups to date, there must be a plethora of such startup ideas left untouched. One example is DIAJENG LESTARI who started https://hijup.com/, described as "A pioneering Muslim Fashion store. We sell fashion apparel especially for Muslim women ranging from clothing, hijab/headscarf, accessories, and more." Little to no chance the archetypal "white male hacker founder" has that idea.

That's three ideas off the bat, only one of which is bias. It could still be bias, but I feel that points 2 & 3 are at least good candidates for exploration. Personally, I think there must be a lot of low hanging fruit in ideas not aimed at men, and female founders seem ideally poised to have those ideas.

Re: A Way to Detect Bias

#190

Post by yummyfajitas »

vii wrote: post #159
yummyfajitas wrote: post #49

Earlier quoted context omitted.

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%.

This assumes that the populations of A and B are of the same size. A larger sample will tend to have a lower minimum under many real world distributions - a sample of one will have its minimum equal to its maximum. Another reason the use of mins here is not helpful, is that adding one equally awful accepted candidate to group A and B would then remove whatever bias there was according to the test, which is not what w…

No, it doesn't assume or require equality. The p-value you compute for this test will be proportional to the smaller of the sample sizes.

Mins will fail if you conspire to cheat the test, it's true. Very few statistical tests stand up to conspiracy theories.

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