No, India did NOT invent calculus

In a new post, I refute the idea that calculus was invented in India and/or that European calculus was built upon ideas of calculus transmitted from India to Europe.

I then provide the true account of how the development of calculus began. The claim that India (or anywhere else before the 17th century) had invented calculus is based on a fundamental misunderstanding of what "calculus" is.

Calculus is a systematic theory of integration and differentiation, one that didn't exist before the 17th century.

In a new post, I contest the common claim that precolonial India was a rich society.

With qualitative and quantitative evidence, we see that the living standards of Indian commoners were poor. I also trace the origins of the divergence between the West and India. The typical claim is that India once accounted for 25% of the global GDP, which reduced to just 4% after colonialism.

But this tells us nothing about their living conditions before we have accounted for the respective population counts. (These old estimates are also dubious)

African homicide rates are completely dubious

That's what I argue in a recent piece. Consider, for example, Nigeria's homicide rate.

An organization that monitors homicides from news reports find >3x homicides than official counts, and household surveys suggest >10x. There are two major sources that compile national homicide rates across the world, including African countries: WHO and UNODC.

WHO, recognizing the unreliability of African homicide statistics, do not even use the official homicide counts and try to estimate it by other means.

Africa's Poor Numbers – new long post published!

In this piece, I critically examine the quality and availability of data in Africa. I argue that much African data is highly unreliable.

In particular, I look at economic data, criminal justice data, and population data. I'm by no means the first to sound alarm about African data quality. It has previously been called "Africa's statistical tragedy". Similarly, a well-known book "Poor Numbers" critically examines Africa's developmental statistics.

It is not unusual to see claims that intelligent or otherwise able people have fewer children. But is this universal? In the Nordic countries, the opposite seems to the case.

Consider first this data of IQ-fertility for Swedish men born between 1951–1967. The data clearly shows that there is a positive relationship between IQ and fertility. To be fair, this is mostly explained by reduced fertility below average IQ. (Note also that "not tested" have very low fertility, but people who weren't tested tend to have very low IQ).

In my most recent piece, I evaluate whether immigrants tend to assimilate with respect to various social outcomes.

One important outcome is crime. Consider for example the following chart. In Denmark, second-generation immigrants are no less criminal than first-generation. I then went one step further and considered whether differences between different immigrant groups converge. Again, Denmark offers excellent data by nation-of-origin.

There is a remarkable persistence in crime rates between first- and second generation (correlation = 0.9).

The Assimilation Myth — new post published!

Using data from a variety of countries, I show that ethnic disparities in human capital, economic performance, crime and cultural values tend to show substantial persistence across generations. First, I consider whether immigrants assimilate in terms of human capital.

Systematic PISA comparisons show that even second-generation immigrants tend to score much more similar to their parents' country-of-origin than the country they were born and raised in.

In a new article, I argue that, contrary to common belief, the American story is not one of widespread and rapid immigrant assimilation. The "melting pot" metaphor is largely a fiction. It is often said that, during the Age of Mass Migration, European migrants rapidly assimilated.

This is mistaken. Not only did large shares of European immigrants return because they couldn't integrate, disparities between European groups did *not* rapidly disappear.

The weird thing about articles like this is that if they had asked a demographer, they would've known that there's a consensus that immigration cannot solve the problem of ageing populations.

https://twitter.com/Telegraph/status/1904860943638544647

More precisely, the amount of immigration necessary to keep the population age down is extreme and unprecedented. Infrastructure wouldn't even be able to keep up.

It's usually a good idea to read what you're sharing (insofar one is trying to be honest).

The "7 times" figure did not come from the study with 25,000 couples (that's citing an old study, which doesn't replicate). The new large study finds small differences.

https://twitter.com/ask_aubry/status/1901087474627039565

In a previous thread, I tried to review the research on this question. Generally, sex differences tend to be small, and are not rarely in the opposite direction of the claim.

https://x.com/Scientific_Bird/status/1744015029421109727

A comparison between fertility measures in Denmark -- or why over-relying on "total fertility rate" is a mistake

This chart shows three fertility measures: (1) the most commonly used "total fertility rate", (2) completed cohort fertility, and (3) the "tempo-adjusted" TFR. Completed cohort fertility rate is actually the "true" fertility. I.e., it's the actual number of children women have over their lifetime.

The "total fertility rate" uses snapshot data from one given year at a time.

This story gets more and more distorted, further and further removed from reality. Here are the actual facts:

1) Franklin did not take Photo 51.
2) Watson and Crick did not steal Photo 51.
3) Photo 51 was not central for the discovery of the DNA structure.

https://twitter.com/GeniusGTX/status/1896546114326913428

1) Franklin did not take Photo 51.

This one's easy to address. It was actually taken by the PhD student Raymond Gosling, who worked under supervision of Maurice Wilkins and Rosalind Franklin.

Youth robbery in Sweden

In this thread, I will talk about the issue of youth immigrant robbery in Sweden.

The reasons for doing robbery range from feeling bored, to purchase cigarettes, to feel powerful, to wanting to "fight the Swedes", to wanting to humiliate their victims. In the 1990s, a distinct phenomenon of youth robbery became prevalent in places such as Malmö and Stockholm in Sweden. It was almost exclusively young boys targeting other young boys. The perpetrators were usually foreign-born and the victims were usually not.

I don't know where people get these ideas from.

As far as I can tell, there is no convincing evidence that supports this “immediate drop” in female car crash deaths (relative to men's).

Even in the community note, where the same claim is made, the links don't provide any?

https://twitter.com/agraybee/status/1870509836032524345

So I decided to look at car accident deaths over time in the United States, 1999-2022.

Is there any evidence that the female death rate suddenly drops relative to men's? No, the male and female *trends* are almost identical.

The open problem -- the "moving sofa problem" -- has possibly just been solved!

This mathematical problem basically asks "what is the largest area of a 'sofa' that can be maneuvered through a right-angled corner in a hallway of width 1?"

Short thread 🧵 This problem was originally posed by Leo Moser in 1966.

Quickly after, Hammersley (1968) proposed a very simple construction.

Take a semi-circle. Cut it into two. Then fill the gap in between, but leave a smaller semi-circle of empty space to help maneuver the corner.

New study has released personality profiles of 263 occupations.

Short thread of the occupations that are the most extreme with respect to each of the five personality dimension (I will mention only occupations with a sample of at least 100). Neuroticism.

High:
- Visual Artists
- Graphic and Multimedia Designers
- Musicians, Singers and Composers

Low:
- Health Services Managers
- Finance Managers
- Information and Communications Technology Services Managers

Many responses to this misunderstand it. A lot of commenters, in their confusion or ignorance, assume that it must necessarily simply be due to abject poverty and lack of access to other food.

In reality, this is an old cultural tradition that persists from West Africa.

https://twitter.com/jeremykauffman/status/1833965281838006327

Geophagy – the scientific term of the eating of dirt, earth and mud – has been common in many places in Africa, for a variety of purported purposes.

John Hunter (1973) discusses this, and also how the practice diffused to the United States by the African diaspora.

Why poverty is not a major cause of violent crime: macroeconomic evidence

While it is well known that poverty tends to be correlated with violent crime, causally informative evidence usually tells a different story. One important source of evidence is the macroeconomic kind.

If economic factors causally affected violent crime, then, when macroeconomic conditions change within a country or region, you should expect violent crime rates to follow. Economic downfalls should lead to increases in violent crime, and vice versa.

One illustrative example is that the homicide rate actually fell in America during the Great Depression–the opposite of what the causal hypothesis would expect.
But it's not just the Great Depression. In the Handbook of Crime Correlates, Lee et al. review the macroeconomic evidence and find that economic downturns have no systematic effect on violent crime.

More recently, Ludwig & Schnepel (2024) also reviewed macro evidence and also concluded that there is no systematic effect on violent crime.
The COVID economic crisis is yet another example. Hoeboer et al. (2024) reviewed the evidence and found that globally there was no increase in violent crime. If anything, it was in the opposite direction.

The United States famously did experience a homicide rate increase starting in 2020. But a careful analysis of the timing of that homicide increase shows that this was the result of a homicide spike immediately following the death of George Floyd. It should not be considered an economic effect.

Overall, there is no clear indication that macroeconomic downturns result in an increase in violent crime. Often the evidence finds the opposite. This is yet another strong line of evidence against the idea that poverty has a major causal impact on violent crime.
There is also evidence from within-individual studies:

https://x.com/Scientific_Bird/status/1831406728878961131

The moment when the West changed forever, on its trajectory towards the modern world. This is at least what I have argued. This chart is based on my analysis of a database of notable people. But, if you think such a database is too biased to consider, fear not, for much other evidence points to this being an important transition period.

Immigration and crime in Sweden

Recently, I wrote a piece in which analyzed the topic of immigration and crime in Sweden. I have posted some of the findings individually, but I thought it would be useful to compile all the major findings in one place. So, thread below. Immigrants and second-generation immigrants have higher crime rates than people with Swedish background.

As shown in the image, this is true after adjusting for age and sex compositions, and it's true for all major categories of crime.

This chart is wrong.

It might be comparing gun homicides to gun deaths, or something to that effect. Whatever the case, the data is clearly nonsense.

That's unfortunate, because there is a legitimate point to be made.

Short thread.

https://twitter.com/ElijahSchaffer/status/1822843896705028258

Cursory research shows that the firearm homicide rate in West Europe is far lower than portrayed in that figure. A firearm homicide rate of ~0.1 per 100k is common. Even in Sweden, known for having serious issues with gun killings, has a rate of ~0.5 per 100k.