A new, comprehensive preregistered meta-analysis found that, whether the diversity was demographic, cognitive, or occupational, its relationship with performance was near-zero.
These authors were very thorough
Just take a look at the meta-analytic estimates. These are in terms of correlations, and they are corrected for attenuation
These effect sizes are significant due to the large number of studies, but they are very low, even after blowing them up
You may ask yourself: are there hidden moderators?
The answer looks to be 'probably not.' Team longevity, industry sector, performance measures, power distance, year or country of study, task complexity, team interdependence, etc.
None of it really mattered.
Here's longevity:
Here's power distance:
Here's collectivism:
But let's put this into practical terms.
Using these disattenuated effects, if you selected from two groups you expected to have comparable performance otherwise, but one was more diverse, you'd make the 'correct' (higher-performing) decision in 51% of cases (vs. 50%).
That assumes there really hasn't been any bias in what gets published. If there has been, you might want to adjust your estimate downwards towards zero, or upwards if you think the literature was rigged the other way.
The paper paints an unsupportive picture of the idea that diversity on its own makes teams more performant.
How bad are Richard Lynn's 2002 national IQ estimates?
They correlate at r = 0.93 with our current best estimates.
It turns out that they're really not bad, and they don't provide evidence of systematic bias on his part🧵
In this data, Lynn overestimated national IQs relative to the current best estimates by an average of 0.97 points.
The biggest overestimation took place in Latin America, where IQs were overestimated by an average of 4.2 points. Sub-Saharan Africa was underestimated by 1.89 pts.
Bias?
If you look at the plot again, you'll see that I used Lynn's infamously geographically imputed estimates.
That's true! I wanted completeness. What do the non-imputed estimates look like? Similar, but Africa does worse. Lynn's imputation helped Sub-Saharan Africa!
If you use a relative standard to measure poverty, establishing the bottom x% are poor regardless of their absolute income, you will never win the war on poverty.
But President Johnson wanted an absolute standard. With such a standard, the poverty rate has fallen more than 90%🧵
The first thing you have to do to get to this is to adjust the equivalence scale of the official poverty rate, by recreating the poverty thresholds based on the square root of the number of family members rather than the formula used for the Official Poverty Measure (OPM):
The next things you have to do are to change the unit poverty is calculated at to the more reasonable unit, household. Then, you use post-tax income, and finally, you have to get to "full-income" by accounting for transfers, including health insurance (incl. Medicare/caid).
Have you seen these charts on parental time use from Our World in Data, Financial Times, and The Economist?
These graphs are not good🧵
The charts come from Dotti Sani and Treas' (2016) paper in the Journal of Marriage and Family.
They depict, the results of a GLM of time use over time that lacks an equation in the paper. The results shown in the pictures come from their Model 3:
Did they have enough power to test for interactions by country?
My guess? No. Consider that the data for mot hers for Slovenia only used two datapoints to fit a nonlinear model:
This is an image from a scanning electron microscope.
The banner along the bottom is the image metadata. That banner might be useful for detecting fraudulent research
🧵
First thing's first:
Scanning electron microscopes are useful, so they're finding their way into more and more published articles. Across 50 journals' articles published 2010 through early 2023, this has been the trend:
Now remember the metadata in the OP? It's from a TESCAN MAIA3. You know, one of these big, expensive machines.
The label is automatically added to the image, and some older articles cut it off, but newer ones shouldn't.
These were a series of wars fought in 1639 and 1640 between Scottish Covenanters and the English and their Scottish supporters.
These were the first of the Wars of the Three Kingdoms, AKA the British Civil Wars.
The image in the last post depicts the 1638 signing of the National Covenant, an agreement signed by Scots opposing King Charles I's attempts to reform the "Kirk" (Church) of Scotland.
The chief god of the Babylonians was Marduk, and Marduk was a canal digger.
His story and his role in their pantheon are amazing, because it turns out his story is about the birth of statehood🧵
In the Babylonian creation myth Enūma Eliš, Marduk gains his powers and his standing by killing his grandmother after she seeks to kill his father, uncles, aunts, and the other young gods who preemptively killed their father.
After attaining his high position, Marduk becomes the canal digger, the maintainer and controller of water, and thus also the god of fertility.
Fertility? Fertility! Because without controlling the fertile crescent's water, there can be no organized living, farming, or much else