Benjamin E. Lauderdale

The mysterious trend in American heights in the 20th century

Background: The secular trend in the height of the US population has been almost neglected in a comparative perspective, despite its being a useful indicator of early-life biological conditions. Aim: The study estimated the height of the US population and compared it to Western European trends after World War II. Subjects and method: The complete set of NHES and NHANES data were analyzed, collected between 1959 and 2004 by the National Center for Health Statistics, in order to construct trends of the physical stature of US-born men and women limited to non-Hispanic blacks and whites. Also analyzed was the trend in the height of US military personnel whose parents were also born in the USA. The trends and levels were compared with those of several European populations. Results: The increase in the physical stature of US adults slowed down by mid-century concurrent with a substantial acceleration in height attainment in Western and Northern Europe. Military data corroborate this finding in the main. After being the tallest population in the world ever since colonial times, Americans are now shorter than most Western and Northern Europeans and as much as 4.7–5.7 cm shorter than the Dutch, who are the tallest in world today. Conclusion: Given the well-established relationship between adult stature and early-life biological welfare, it was hypothesized that either American diets are sub-optimal or that the universal health care systems and social safety net of the European welfare states are providing a more favorable early-life health environment than does the American health care system.

The Paramecium Germline Genome Provides a Niche for Intragenic Parasitic DNA: Evolutionary Dynamics of Internal Eliminated Sequences

Insertions of parasitic DNA within coding sequences are usually deleterious and are generally counter-selected during evolution. Thanks to nuclear dimorphism, ciliates provide unique models to study the fate of such insertions. Their germline genome undergoes extensive rearrangements during development of a new somatic macronucleus from the germline micronucleus following sexual events. In Paramecium, these rearrangements include precise excision of unique-copy Internal Eliminated Sequences (IES) from the somatic DNA, requiring the activity of a domesticated piggyBac transposase, PiggyMac. We have sequenced Paramecium tetraurelia germline DNA, establishing a genome-wide catalogue of ∼45,000 IESs, in order to gain insight into their evolutionary origin and excision mechanism. We obtained direct evidence that PiggyMac is required for excision of all IESs. Homology with known P. tetraurelia Tc1/mariner transposons, described here, indicates that at least a fraction of IESs derive from these elements. Most IES insertions occurred before a recent whole-genome duplication that preceded diversification of the P. aurelia species complex, but IES invasion of the Paramecium genome appears to be an ongoing process. Once inserted, IESs decay rapidly by accumulation of deletions and point substitutions. Over 90% of the IESs are shorter than 150 bp and present a remarkable size distribution with a ∼10 bp periodicity, corresponding to the helical repeat of double-stranded DNA and suggesting DNA loop formation during assembly of a transpososome-like excision complex. IESs are equally frequent within and between coding sequences; however, excision is not 100% efficient and there is selective pressure against IES insertions, in particular within highly expressed genes. We discuss the possibility that ancient domestication of a piggyBac transposase favored subsequent propagation of transposons throughout the germline by allowing insertions in coding sequences, a fraction of the genome in which parasitic DNA is not usually tolerated.

Crowd-sourced text analysis: reproducible and agile production of political data

Empirical social science often relies on data that are not observed in the field, but are transformed into quantitative variables by expert researchers who analyze and interpret qualitative raw sources. While generally considered the most valid way to produce data, this expert-driven process is inherently difficult to replicate or to assess on grounds of reliability. Using crowd-sourcing to distribute text for reading and interpretation by massive numbers of nonexperts, we generate results comparable to those using experts to read and interpret the same texts, but do so far more quickly and flexibly. Crucially, the data we collect can be reproduced and extended transparently, making crowd-sourced datasets intrinsically reproducible. This focuses researchers’ attention on the fundamental scientific objective of specifying reliable and replicable methods for collecting the data needed, rather than on the content of any particular dataset. We also show that our approach works straightforwardly with different types of political text, written in different languages. While findings reported here concern text analysis, they have far-reaching implications for expert-generated data in the social sciences.

The Supreme Court's Many Median Justices

One-dimensional spatial models have come to inform much theorizing and research on the U.S. Supreme Court. However, we argue that judicial preferences vary considerably across areas of the law, and that limitations in our ability to measure those preferences have constrained the set of questions scholars pursue. We introduce a new approach, which makes use of information about substantive similarity among cases, to estimate judicial preferences that vary across substantive legal issues and over time. We show that a model allowing preferences to vary over substantive issues as well as over time is a significantly better predictor of judicial behavior than one that only allows preferences to vary over time. We find that judicial preferences are not reducible to simple left-right ideology and, as a consequence, there is substantial variation in the identity of the median justice across areas of the law during all periods of the modern court. These results suggest a need to reconsider empirical and theoretical research that hinges on the existence of a single pivotal median justice.

Spatial correlates of us heights and body mass indexes, 2002.

Aiming to further explore possible underlying causes of the recent remarkable stagnation and relative decline in American heights, this paper describes the result of analysis of the commercial US Sizing Survey (2002). Heights are correlated positively with income and education among both white males and females while Body Mass Index (BMI) is correlated negatively among females, as in other samples. In contrast to much of the literature, this paper considers geographic correlates of height such as local poverty rate, median income and population density at the zip code level of resolution. After adjusting for confounding factors that influence height such as income and education, population density is found to be strongly and negatively correlated with height among white men, but less so among white women. The effect on BMIs less convincing. Other ethnic groups are not analysed in detail because of the small number of observations available. Local economic conditions as measured by median income, unemployment and poverty rate do not have a strong correlation with height or BMI after adjusting for individual income and education.

A partisan gap in the supply of female potential candidates in the United States

A partisan disparity in women representatives in the US House emerged in the 1980s and has continued to grow in magnitude. We show that this pattern closely mirrors the emergence of a partisan disparity in the proportion of women in the US public with the typical characteristics of high-level officeholders. Our analysis indicates that the proportion of women in the Democratic pool of potential candidates is now two to three times larger than in the Republican pool of potential candidates. Given the current association of party identification with gender and other characteristics, this gap is more likely to increase than decrease over the coming decade, with potential consequences for the descriptive and substantive representation of women in American politics.

Decomposing public opinion variation into ideology,idiosyncrasy and instability

We propose a method for decomposing variation in the issue preferences that US citizens express on surveys into three sources of variability that correspond to major threads in public opinion research. We find that, averaging across a set of high-profile US political issues, a single ideological dimension accounts for about 1/7 of opinion variation, individuals’ idiosyncratic preferences account for about 3/7, and response instability for the remaining 3/7. These shares vary substantially across issue types, and the average share attributable to ideology doubles when a second ideological dimension is permitted. We also find that (unidimensional) ideology accounts for almost twice as much response variation (and response instability is substantially lower) among respondents with high, rather than low, political knowledge. Our estimation strategy is based on an ordinal probit model with random effects and is applicable to other data sets that include repeated measurements of ordinal issue position data.

Never Let a Good Crisis Go to Waste: Agenda Setting and Legislative Voting in Response to the EU Crisis

The European Union’s policy response to the recent global economic crisis transferred significant powers from the national to the European level. When exogenous shocks make status quo policies less attractive, legislators become more tolerant to proposed alternatives, and the policy discretion of legislative agenda setters increases. Given control of the EU agenda-setting process by pro-integration actors, we argue that this dynamic explains changes in voting patterns of the European Parliament during the crisis period. We observe voting coalitions increasingly dividing legislators along the pro-anti integration, rather than the left-right dimension of disagreement, but only in policy areas related to the crisis. In line with more qualitative assessments of the content of passed legislation, the implication is that pro-integration actors were able to shift policy further toward integration than they could have without the crisis.

Estimating Vote-Specific Preferences from Roll-Call Data Using Conditional Autoregressive Priors

Ideal point estimation in political science usually aims to reduce a matrix of votes to a small number of preference dimensions. We argue that taking a nonparametric perspective can yield measures that are more useful for some subsequent analyses. We propose a conditional autoregressive preference measurement model, which we use to generate case-specific preference estimates for US Supreme Court justices from 1946 to 2005. We show that the varying relative legal positions taken by justices across areas of law condition the opinion assignment strategy of the chief justice and the decisions of all justices as to whether to join the majority opinion. Unlike previous analyses that have made similar claims, using case-specific preference estimates enables us to hold constant the justices involved, providing stronger evidence that justices are strategically responsive to each others’ relative positions on a case-by-case basis rather than simply their identities or average relative preferences.