On the value of anecdotes

331 words

What is better, if everyone is wrong about the same 2% of facts, or if everyone is wrong about a different 4% of facts? Depending on how you answer this question, you should act in very different ways. I’ll take vegan advocacy as an example, but the question can be applies more generally.

If you’re in the first group, you would prefer a scientific data-driven approach. You would experiment with many different approaches to advocacy, analyse the data to find the single best way of doing outreach, and make everyone in vegan activism aware that this is the best way to do it.

If you prefer the 4% case, a local algorithm is the way to go. Think about what drove you to become vegan, and continue this strategy. If you were shocked into becoming vegan by a Cube of Truth, you should be participating in Cubes of Truth. If you became vegan after your friendly vegan neighbour exemplified that veganism is a totally normal lifestyle and they allowed you to pick their brain about why they became vegan themselves, then you should become the friendly vegan acquaintance of the people you know yourself.

One interesting question if you enact the local algorithm, is how to weigh anecdotes. The local algorithm described above only considers your data; one alternative algorithm is to use the approach that was effective on the majority of your direct friends that became vegan before you. Another algorithm looks at all your the friends of your friends, or everyone within distance 3 in the friendship-graph. If everyone is connected by everyone by a friendship-path of length 6, then the distance 6 algorithm is exactly the data-driven approach from the second paragraph.

Evolutionary theory suggests that the small-distance algorithms are effective, for the best outreach strategy will eventually out-compete all others. But for the distance 0 or 1 cases, you’re basically working on anecdotal evidence. I’m not sure anymore what the correct value is to place on anecdotes.

The life expectancy of trans women is not 35 years

904 wordsEvery once in a while I read an article or comment like this:

The average lifespan of trans women in the US is 35 years. Source

This number is wrong in so many ways, but many people seem to fall for it. The most viral variant consists of screencaps of this tumblr post.

User fuckallies on tumblr: 'On average, you have a 1 in 18,989 chance of being murdered A trans person has a 1 in 12 chance of being murdered The average life span of a cis person is about 75-90 The average life expectancy of a trans person is 23-30 years old 75% of people killed in anti LGBT hate crimes are poc Think about this the next time you go crying over “cisphobia” and “reverse racism”'

Every murder is a tragedy, and it is particularly sad when someone gets murdered just for being trans. That is all the more reason to get our numbers right: exaggeration doesn’t help the cause. The lifespan statistic above is absurd. There is no way that they can be true, and it is telling of our maths and science education that people believe them.

Let’s do a basic sanity check on the 23-30 years figure. If 50% of trans folks would reach the age of 60, the other half would have to be dead by age 10. But measuring “age of death of trans people” is really tricky, because a person will only enter the trans population after transition: if they die before that, nobody knows they’re trans. So realistically, all trans people that die are at least 16 years old.  If the trans people who get murdered do so at the earliest possible age (16), how many trans people can maximally reach the age of 75? Well, we solve for the fraction x:75x + (1-x)*16=35.

Does one in 3 trans people get killed over their lives? Of course not. The only place the 23-30 year figure could realistically come from is if the number described life expectancy conditional on getting killed or some other low-probability conditional.

Media reporting

Most journalists aren’t good with numbers. This effects their propensity to cite the low life expectancy for trans folks. The Guardian:

a 2014 report concluded that the average life expectancy of trans women in the Americas is between 30 and 35.

NPR:

“Transgender people have an average life expectancy of about 30 to 32 years,” Balestra says.

Huffington Post:

The statistic said the average life expectancy for a trans woman of color is 35.

The difference is striking. “transgender people”, “trans women in the US”, “trans women in the Americas”, “trans women of colour”. They’re all misreporting the same in number in different messed up ways.

The first popular English medium to cover the number, and the source that most chains of web pages end up on, is Washington Blade, which reports one realistic number and also the unrealistic one.

The commission indicates 80 percent of trans murder victims in the Americas during the 15-month period were 35 years old or younger. Its report further concludes the average life expectancy of trans people in the Western Hemisphere is between 30-35 years.

Washington Blade cites a report by the Inter-American Commission on Human Rights of the Organisation of American States (press release, report). The report mentions this

According to the data collected in the Registry of Violence, eighty percent of trans persons killed were 35 years of age or younger.

The data (xlsx, Spanish) contains 770 reports of violence against LGBT people from a lot of countries in the Americas, all incidents happened in the 15 months between January 1st 2013 and March 31st 2014. Not all countries are in the dataset and no skin colours of the victims are listed, but are. Some victims are deadnamed, others appropriately named. Searching the names online, there are indeed a lot of trans women of colour among the listed US victims.

The data contain 282 murders on trans people, of which 212 have an age of death attached. The average age of death among those 212 is 28.7. Among 14 murder cases in the US, all trans women, the average age was 29.8. Filtering the America-wide data for listed ages of murder of 35 and under, we find 168 cases, and 168 out of 212 is 80%. This is the source of the 80% vs 35 years claim, but keep in mind that this is as a fraction of cases that have ages attached to them.

Where does the life expectancy of 30-35 years come from? The IACHR report just says this:

In terms of the age of the victims, the IACHR notes that while it seems gay men of all ages are targeted, in the case of trans women, it is mostly younger trans women who are victims of violence. In this regard, the IACHR has received information that the life expectancy of trans women in the Americas is between 30 and 35 years of age.

No source is listed. I’m calling bullshit. There is no way that getting murdered reduces life expectancy by at most 5 years.

Section of doubt

The 1 in 12 murder rate up top is interesting because it cannot be refuted in a conservative street-fighting calculation.  The US has 325 million citizens and a life expectancy of 79 years, so every year roughly 4.1 million US citizens die. If 1 in 40000 people is trans, then you’d expect 100 US trans people to die each year. 2018’s TDOR has 23 murder cases from the US listed, so we’d estimate that trans people have a 1 in 4 probability of death by murder, not accounting for skin color.

I don’t trust the 1:40000 statistic within an order of magnitude, but it is an often cited one. So while I don’t take the 1:4 number to be remotely close to the truth, it is understandable if people believe the 1 in 12 figure.

Abstinence-Only Education Criticism | Part 2

172 wordsDue to recent events, here is a part 2 to my earlier post on abstinence “treatment”. Slightly more personal this time.

Eating Disorders

Reddit just banned /r/ProED and /r/ProEDmemes. I’m not sure what to say, other than that it sucks.

I’ve never had an eating disorder. I’ve flirted with it and my eating has never been healthy, but it has never interfered with my day-to-day functioning.

I liked ProEDmemes. Many posts were relatable, and the community has helped me through some dark spots. The people were lovely and caring, it was a place to relate and to vent. It wasn’t a place where eating disorders were encouraged, but one where eating disorders were accepted and everyone could work it out on their own pace, sharing and receiving help along the way.

Reddit is really convenient. You can easily participate in many different communities at once, so any single community can survive even when little fresh content gets posted. But for vulnerable communities, it doesn’t work so well.

I miss the old internet.

Veg*n dishes versus constrained optimization

313 wordsMathematical optimization is concerned with  problems of the form \text{maximize~} f(x) \text{~ for ~} x \in X for some set X \subset Y and function f : Y \to \mathbb{R}. In this post, we’ll think of Y as the set of possible restaurant dishes, X\subset Y as the set of dishes satisfying certain constraints like being digestible, non-poisonous and not containing human flesh. The function f to optimize is some combination of price, healthyness and taste.

A first observation is that for any X' \subset X the maximum of f(x) over X' is no bigger than the maximum over X, for if x \in X' attains the maximum of f(x) over X', then also x \in X, so the maximum of f over X is at least f(x). In normal words, if you restrict your diet, you can miss out on good dishes, but never gain access to better dishes than on an unrestricted diet.

From this, we could deduce that you should never pick a vegan dish in a restaurant because the non-vegan dishes were made with fewer restrictions and hence can only be better than the vegan dish. Same for choosing recipes to cook yourself. Before I was vegan, this was my conscious reason for always choosing dishes with meat.

But is the deduction true? I don’t think so. Because, unbeknownst to many, the meat dishes are actually constrained to contain meat. I don’t know why, but my two prime suspects are Goodhart’s law impacting the reasoning above, or meat-eaters being scared of vegetables.

As it turns out, making a good vegetarian meal takes non-zero skill, contrary to making a good meal with meat. In my experience, this causes chefs to put actual thought into their vegetarian dishes, causing these to actually be tastier than most dishes with meat. So the argument from mathematical optimization actually gives the wrong answer here!

Abstinence-only education criticism as general template

540 wordsTW: self-harm, suicide, substance abuse

Context: In conservative regions in the US, there is a thing called abstinence-only sex education. People believe that you can tell teenagers “Don’t have sex before marriage” and that that will protect them from STI’s and unwanted pregnancy. Leftist people point to research that shows this is ineffective, and it is much better to tell kids how to have sex safely. I have not looked at the research so I will not link it.

If you squint, you can see how abstinence-only education is used for other things as well. It makes me wonder whether the same criticism would transfer.

Self-harm

One area to which it might transfer is self-harm. Everybody says you should not self-harm. In many psychiatric hospitals, you may temporarily lose privileges (being allowed to watch tv or to go outside) if the staff thinks you have self-harmed while there.

If you search online for “self-harm tips”, the first result is a wordy self-righteous “Don’t do that“. I used to find this really really frustrating. Same goes for online self-harm communities: they mostly forbid giving instructions and such.  Positively helpful stuff gets silenced, like when Reddit banned /r/selfharmpics. Ironically, that sub used to help me get my thoughts away from harming myself by living it vicariously through others.

Here is a link to some good self-harm tips and advice. Though I can think of a dozen other pieces of information that could help a lot of people. Examples include:

  • Hiding scars: What parts of the body scar the least? What body parts are least visible in common positions?
  • Preventing scarring: How much do anti-scarring creams really help? Do cuts with sharp or dull blades make for less visible scars?
  • Safely climbing the hedonic treadmill: a list of body parts sorted by sensitivity to pain would help people to safely get more painful wounds without cutting deeper.
  • What is a good place to cut when you are just starting out?

Some of these things you can maybe find online if you know the academic jargon, but that won’t help most self-harming persons.

Suicide

I have no idea if the abstinence-only criticism would meaningfully transfer to suicide. But at least this area does have educational resources provided by helpful individuals, like http://lostallhope.com/. I never found this website before I started researching for this post, but it might not have had much PageRank credit back when I was looking for these things. [Also santioned-suicide.com]

Drugs

This is an obvious case where the abstinence-only education criticism directly transfers. Some substances are way worse for your health than others, so it would be good if people knew which those are, even if one would also recommend to not do them at all.

My high school actually did this. They were pretty backwards in many respects, but here, they were on point. We got a guest lesson by a cool lady who had tried all kinds of drugs. She told us about various kinds of drugs and what they do, and we got to ask all kinds of questions. I mostly remember her warning that heroin is super addictive, like, a single use and you’re addicted. That was a great lesson, and exactly the sort of thing I want to see on more issues.

Asymmetry of passion

241 wordsSome time ago I first read the phrase “asymmetry of passion” in an article (in Wired via Kottke) about so-called “keyword voids” in internet search engines. The article starts by discussing the internet search results for “vitamin K shots”, a routine injection that newborns get.

This is a routine practice—ask your pediatrician, your obstetrician, or the CDC. “Babies are born with very low stores of vitamin K, and without the Vitamin K shot … they do not have enough Vitamin K in their blood to form a clot,” the CDC says on its website.

But new parents who turn to search engines to understand the practice will find an aberrant—and dangerous—strain of thinking. Google “vitamin K shot” and the first result advises “Skip that Newborn Vitamin K Shot.” It isn’t until below the fold—the fourth result—that the CDC website appears.

This is blamed on an asymmetry of passion; anti-vaxxers put much more effort into writing blogs stating that the shots are unnecessary or even dangerous than government organizations like the CDC do to refute their claims. Hence the search results get populated with all-natural anti-science lies. (I just tried the search and my results page only has a single anti-vax result. The Wired article caused a number of scientifically literate websites write about the vitamin K shots.)

Asymmetries of passion happen more often. [A couple of situations where I think something like that is happening include blockchain, political videos on Youtube, and conspiracy theories.

Archiving the Trans Girl Diaries

209 wordsBetween standing on the shoulders of giants and picking through my own old files, I compiled the most complete archive of the Trans Girl Diaries gag comics so far. Check it out, this stuff is amazing.

Where do these things come from?

Turns out I used wget’s mirror function on the website once. The most bulletproof setting for this command is

wget -mkE http://example.com

This stuff is so great. It makes a copy of an entire website, including all pages, images, CSS and Javascript. Use it to grab a blog for reading on the plane, to make a static WordPress site if you are worried about security exploits but dislike updating, or to save your favourite webcomic for posterity.

Trigger warnings

Suicide, gender dysphoria, violence, external transphobia, internalized transphobia, Bailey-Blanchard-Lawrence two-type transwomen classification, transphobia, really intense descriptions of gender dysphoria, TERFism, sexism, homophobia, womyn-born-womyn-ism, Harry Benjamin syndrome and an altogether too realistic view of transgenderism.

If you like r/tgcj you’ll probably like the Trans Girl Diaries.

Review

I love this stuff. The comics meant a lot to me when I was younger. They are relatable and funny and give insight into all the disturbing thoughts that are part of the Trans Woman Experience. Whether you are trans or not, it is worth checking out.

Links #1: Modern computers are complicated

266 wordsDavid Chisnall: C is not a low-level language

A modern Intel processor has up to 180 instructions in flight at a time (in stark contrast to a sequential C abstract machine, which expects each operation to complete before the next one begins). A typical heuristic for C code is that there is a branch, on average, every seven instructions. If you wish to keep such a pipeline full from a single thread, then you must guess the targets of the next 25 branches. This, again, adds complexity; it also means that an incorrect guess results in work being done and then discarded, which is not ideal for power consumption. This discarded work has visible side effects, which the Spectre and Meltdown attacks could exploit.

Matt Klein: Meltdown and Spectre, explained

Each cache miss adds a substantial amount of delay time to program execution. In order to mitigate this, processors are capable of executing ahead and out of order while waiting for memory loads. This is known as speculative execution. The following code snippet demonstrates this.

if (x < array1_size) {
  y = array2[array1[x] * 256];
}

In the previous snippet, imagine that array1_size is not available in cache, but the address of array1 is. The CPU might guess (speculate) that x is less than array1_size and go ahead and perform the calculations inside the if statement. Once array1_size is read from memory, the CPU can determine if it guessed correctly. If it did, it can continue having saved a bunch of time. If it didn’t, it can throw away the speculative calculations and start over. This is no worse than if it had waited in the first place.