Publication Type: (Journal Article)

Correcting Measurement Error Bias in Conjoint Survey Experiments
Katherine Clayton, Yusaku Horiuchi, Aaron R. Kaufman, Gary King, and Mayya Komisarchik. Working Paper. “Correcting Measurement Error Bias in Conjoint Survey Experiments”.Abstract

Conjoint survey designs are spreading across the social sciences due to their unusual capacity to estimate many causal effects from a single randomized experiment. Unfortunately, by their ability to mirror complicated real-world choices, these designs often generate substantial measurement error and thus bias. We replicate both the data collection and analysis from eight prominent conjoint studies, all of which closely reproduce published results, and show that a large proportion of observed variation in answers to conjoint questions is effectively random noise. We then discover a common empirical pattern in how measurement error appears in conjoint studies and, with it, introduce an easy-to-use statistical method to correct the bias.

You may be interested in software (in progress) that implements all the suggestions in our paper: "Projoint: The One-Stop Conjoint Shop".

How American Politics Ensures Electoral Accountability in Congress
Danny Ebanks, Jonathan N. Katz, and Gary King. Working Paper. “How American Politics Ensures Electoral Accountability in Congress”.Abstract

An essential component of democracy is the ability to hold legislators accountable via the threat of electoral defeat, a concept that has rarely been quantified directly. Well known massive changes over time in indirect measures — such as incumbency advantage, electoral margins, partisan bias, partisan advantage, split-ticket voting, and others — all seem to imply wide swings in electoral accountability. In contrast, we show that the (precisely calibrated) probability of defeating incumbent US House members has been surprisingly constant and remarkably high for two-thirds of a century. We resolve this paradox with a generative statistical model of the full vote distribution to avoid biases induced by the common practice of studying only central tendencies, and validate it with extensive out-of-sample tests. We show that different states of the partisan battlefield lead in interestingly different ways to the same high probability of incumbent defeat. Many challenges to American democracy remain, but this core feature remains durable.
 

If a Statistical Model Predicts That Common Events Should Occur Only Once in 10,000 Elections, Maybe it’s the Wrong Model
Danny Ebanks, Jonathan N. Katz, and Gary King. Working Paper. “If a Statistical Model Predicts That Common Events Should Occur Only Once in 10,000 Elections, Maybe it’s the Wrong Model”.Abstract

Political scientists forecast elections, not primarily to satisfy public interest, but to validate statistical models used for estimating many quantities of scholarly interest. Although scholars have learned a great deal from these models, they can be embarrassingly overconfident: Events that should occur once in 10,000 elections occur almost every year, and even those that should occur once in a trillion-trillion elections are sometimes observed. We develop a novel generative statistical model of US congressional elections 1954-2020 and validate it with extensive out-of-sample tests. The generatively accurate descriptive summaries provided by this model demonstrate that the 1950s was as partisan and differentiated as the current period, but with parties not based on ideological differences as they are today. The model also shows that even though the size of the incumbency advantage has varied tremendously over time, the risk of an in-party incumbent losing a midterm election contest has been high and essentially constant over at least the last two thirds of a century.

Please see "How American Politics Ensures Electoral Accountability in Congress," which supersedes this paper.
 

Statistical Intuition Without Coding (or Teachers)
Natalie Ayers, Gary King, Zagreb Mukerjee, and Dominic Skinnion. Working Paper. “Statistical Intuition Without Coding (or Teachers)”.Abstract
Two features of quantitative political methodology make teaching and learning especially difficult: (1) Each new concept in probability, statistics, and inference builds on all previous (and sometimes all other relevant) concepts; and (2) motivating substantively oriented students, by teaching these abstract theories simultaneously with the practical details of a statistical programming language (such as R), makes learning each subject harder. We address both problems through a new type of automated teaching tool that helps students see the big theoretical picture and all its separate parts at the same time without having to simultaneously learn to program. This tool, which we make available via one click in a web browser, can be used in a traditional methods class, but is also designed to work without instructor supervision.
 
Differentially Private Survey Research
Georgina Evans, Gary King, Adam D. Smith, and Abhradeep Thakurta. Forthcoming. “Differentially Private Survey Research.” American Journal of Political Science.Abstract
Survey researchers have long sought to protect the privacy of their respondents via de-identification (removing names and other directly identifying information) before sharing data. Although these procedures can help, recent research demonstrates that they fail to protect respondents from intentional re-identification attacks, a problem that threatens to undermine vast survey enterprises in academia, government, and industry. This is especially a problem in political science because political beliefs are not merely the subject of our scholarship; they represent some of the most important information respondents want to keep private. We confirm the problem in practice by re-identifying individuals from a survey about a controversial referendum declaring life beginning at conception. We build on the concept of "differential privacy" to offer new data sharing procedures with mathematical guarantees for protecting respondent privacy and statistical validity guarantees for social scientists analyzing differentially private data.  The cost of these new procedures is larger standard errors, which can be overcome with somewhat larger sample sizes.
Statistically Valid Inferences from Privacy Protected Data
Georgina Evans, Gary King, Margaret Schwenzfeier, and Abhradeep Thakurta. Forthcoming. “Statistically Valid Inferences from Privacy Protected Data.” American Political Science Review. Publisher's VersionAbstract
Unprecedented quantities of data that could help social scientists understand and ameliorate the challenges of human society are presently locked away inside companies, governments, and other organizations, in part because of privacy concerns. We address this problem with a general-purpose data access and analysis system with mathematical guarantees of privacy for research subjects, and statistical validity guarantees for researchers seeking social science insights. We build on the standard of ``differential privacy,'' correct for biases induced by the privacy-preserving procedures, provide a proper accounting of uncertainty, and impose minimal constraints on the choice of statistical methods and quantities estimated. We also replicate two recent published articles and show how we can obtain approximately the same substantive results while simultaneously protecting the privacy. Our approach is simple to use and computationally efficient; we also offer open source software that implements all our methods.
The Essential Role of Statistical Inference in Evaluating Electoral Systems: A Response to DeFord et al.
Jonathan Katz, Gary King, and Elizabeth Rosenblatt. Forthcoming. “The Essential Role of Statistical Inference in Evaluating Electoral Systems: A Response to DeFord et al.” Political Analysis.Abstract
Katz, King, and Rosenblatt (2020) introduces a theoretical framework for understanding redistricting and electoral systems, built on basic statistical and social science principles of inference. DeFord et al. (Forthcoming, 2021) instead focuses solely on descriptive measures, which lead to the problems identified in our arti- cle. In this paper, we illustrate the essential role of these basic principles and then offer statistical, mathematical, and substantive corrections required to apply DeFord et al.’s calculations to social science questions of interest, while also showing how to easily resolve all claimed paradoxes and problems. We are grateful to the authors for their interest in our work and for this opportunity to clarify these principles and our theoretical framework.
 
A simulation-based comparative effectiveness analysis of policies to improve global maternal health outcomes
Zachary J. Ward, Rifat Atun, Gary King, Brenda Sequeira Dmello, and Sue J. Goldie. 4/20/2023. “A simulation-based comparative effectiveness analysis of policies to improve global maternal health outcomes.” Nature Medicne. Publisher's VersionAbstract
The Sustainable Development Goals include a target to reduce the global maternal mortality ratio (MMR) to less than 70 maternal deaths per 100,000 live births by 2030, with no individual country exceeding 140. However, on current trends the goals are unlikely to be met. We used the empirically calibrated Global Maternal Health microsimulation model, which simulates individual women in 200 countries and territories to evaluate the impact of different interventions and strategies from 2022 to 2030. Although individual interventions yielded fairly small reductions in maternal mortality, integrated strategies were more effective. A strategy to simultaneously increase facility births, improve the availability of clinical services and quality of care at facilities, and improve linkages to care would yield a projected global MMR of 72 (95% uncertainty interval (UI) = 58–87) in 2030. A comprehensive strategy adding family planning and community-based interventions would have an even larger impact, with a projected MMR of 58 (95% UI = 46–70). Although integrated strategies consisting of multiple interventions will probably be needed to achieve substantial reductions in maternal mortality, the relative priority of different interventions varies by setting. Our regional and country-level estimates can help guide priority setting in specific contexts to accelerate improvements in maternal health.
Simulation-based estimates and projections of global, regional and country-level maternal mortality by cause, 1990–2050
Zachary J. Ward, Rifat Atun, Gary King, Brenda Sequeira Dmello, and Sue J. Goldie. 4/20/2023. “Simulation-based estimates and projections of global, regional and country-level maternal mortality by cause, 1990–2050.” Nature Medicine. Publisher's VersionAbstract
Maternal mortality is a major global health challenge. Although progress has been made globally in reducing maternal deaths, measurement remains challenging given the many causes and frequent underreporting of maternal deaths. We developed the Global Maternal Health microsimulation model for women in 200 countries and territories, accounting for individual fertility preferences and clinical histories. Demographic, epidemiologic, clinical and health system data were synthesized from multiple sources, including the medical literature, Civil Registration Vital Statistics systems and Demographic and Health Survey data. We calibrated the model to empirical data from 1990 to 2015 and assessed the predictive accuracy of our model using indicators from 2016 to 2020. We projected maternal health indicators from 1990 to 2050 for each country and estimate that between 1990 and 2020 annual global maternal deaths declined by over 40% from 587,500 (95% uncertainty intervals (UI) 520,600–714,000) to 337,600 (95% UI 307,900–364,100), and are projected to decrease to 327,400 (95% UI 287,800–360,700) in 2030 and 320,200 (95% UI 267,100–374,600) in 2050. The global maternal mortality ratio is projected to decline to 167 (95% UI 142–188) in 2030, with 58 countries above 140, suggesting that on current trends, maternal mortality Sustainable Development Goal targets are unlikely to be met. Building on the development of our structural model, future research can identify context-specific policy interventions that could allow countries to accelerate reductions in maternal deaths.
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