Author: Jay M

Racial disparities in intergenerational mobility

In this post, I explore racial disparities in intergenerational mobility, i.e. racial disparities in offspring outcomes after controlling for parental achievement on the same outcome. The primary focus is on black-white disparities in income mobility, i.e. the finding that black children have lower incomes than white children with similar parental incomes. However, other racial groups and socioeconomic outcomes will be considered when data is available. I start by documenting racial disparities in various socioeconomic outcomes, such as income, educational attainment, and wealth. I also show that there are also large racial disparities in mobility for each of these outcomes. Next, I document some of the patterns of income mobility gaps in more detail, by showing the history of the gap, how the gaps vary by sex, and making comparisons with racial groups other than blacks and whites. Following that, I explain why differences in income mobility are pivotal to explaining persistent income gaps between blacks and whites. I then consider a number of different factors that might explain black-white gaps in income mobility. Finally, I end by considering what I take to be important implications of these findings.

Racial preferences at elite American universities

In this post, I explore racial preferences in elite universities in the United States. I’ll start by outlining the basic racial demographics of top universities. Then I’ll compare this data to the demography of top achieving American high schoolers. This comparison highlights the consequences of extreme racial preferences in the admissions process of our elite institutions of higher education. Next, I’ll estimate the demography of top universities after separating Jewish whites and non-Jewish whites. My estimates suggest the surprising finding that non-Jewish whites are perhaps the most under-represented racial group at these elite institutions.

Following that, I’ll review studies that attempt to quantify the magnitude and patterns of racial preferences at selective universities. These reviews reveal the surprising finding that elite universities have little to no preferences for low-SES or low-income applicants. Next, I briefly cite a few reviews of affirmative action case law, in order to understand the primary legal defenses of racial preferences that have been presented by selective universities in landmark Supreme Court cases. The review of affirmative action case law leaves me with a few important questions which I believe have not been adequately addressed by elite universities. Finally, I end the post explaining why racial preferences at elite universities are important.

The causal influence of cognitive ability

In a previous post, I cited data showing that cognitive ability is significantly correlated with various important outcomes, such as academic achievement, occupational performance, socioeconomic status, anti-social behavior, and health. However, that data only establishes that there is a statistical association between cognitive ability and these outcomes. The data does not establish that cognitive ability has a causal influence on any of these outcomes. In this post, I will provide evidence that cognitive ability has a causal influence on academic achievement, occupational performance, socioeconomic success, and anti-social behavior.

Causal inference in social science

The purpose of this post is to provide some guidelines to aid in inferring causation in social science research. At the moment, the post just defines confounding variables, distinguishes them from other third-variables (e.g. mediators and colliders), and provides some examples of statistical techniques that can be used to control for confounding variables. In the future, I hope to cover in more detail regression analysis, causal diagrams, multicollinearity, and other concepts important to understand to infer causation in the social sciences.

The predictive validity of cognitive ability

There is overwhelming evidence showing the predictive validity of cognitive ability for important life outcomes. Cognitive ability measured as early as age 6 has a strong association with one’s future success in a number of important outcomes, including academic achievement, occupational performance, income, educational attainment, occupational prestige, criminality, self-control, and health. The associations are typically large, often making cognitive ability the best predictor for such outcomes. In this post, I will cite research showing this evidence. I will begin with some background on cognitive ability, including definitions, the distributions of IQ test scores, the stability of cognitive ability test scores, and expert consensus on the validity of cognitive ability. Finally, I will cite data demonstrating the predictive validity of cognitive ability in academic achievement, occupational performance, socioeconomic success, anti-social behavior, and health.

Interpreting Effect Sizes

Note: this post is a work in progress. The effect size is a statistic that quantifies the magnitude of the association between two variables. It is arguably the most important statistic reported in any study attempting to report the relationship between different variables. This purpose of this post is to aid in interpreting effect sizes, particularly from a social science perspective. There are several different kinds of statistics that are used to report effect sizes, […]

The predictive validity of cognitive ability (OLD)

There is overwhelming evidence demonstrating the undeniable predictive validity of cognitive ability. Cognitive ability measured as early as age 6 has a strong association with one’s future success in a number of important outcomes, including income, educational attainment, academic performance, occupational prestige, occupational performance, criminality, etc. These associations are robust, persisting even after controlling for a number of plausible confounding variables, including parental socioeconomic status, race, job training and job experience, and other risk factors for the relevant life outcomes. The totality of evidence heavily implies that this association is causal, indicating that early cognitive ability is a powerful factor in determining a person’s chances of achieving conventional measures of success in Western societies.

A sketch of plausible libertarian ownership rights

I will describe in this post what I take to be the most plausible form of libertarianism. Because there are so many different topics and issues related to libertarianism, I will mainly sketch over a large variety of topics without going deep into any particular issue. This post is meant as an exercise to formulate, rather than justify, my preferred form of libertarianism.

Achievement beyond IQ: childhood self-regulation

In previous posts, I have emphasized the predictive power of IQ on a variety of outcomes such as education academic achievement, educational attainment, occupational prestige, income, and crime. I referenced studies showing that IQ is a better predictor of many of these outcomes compared to other metrics traditionally assumed to predict success. For example, many studies show that IQ predicts education, occupation, and income better than many metrics that people assume to be predictors of success – e.g. parental SES, parental income, parental education, etc. Such data might lead some to believe that IQ is by far the single best predictor of conventional measures of success within Western societies. I wish to challenge that idea in this post. I do not necessarily deny that IQ is generally the best predictor of certain measures of success. Rather, I insist that there are a variety of personality traits that are better predictors for certain measures of success. There are many personality traits that I could use to support my argument, such as conscientiousness or locus of control. In this post, I will focus on self-regulation. I will present data showing that self-regulation predicts a variety of important outcomes independent of various confounders (including IQ and parental SES).

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