Article

The following initiative showcases the working papers of Columbia's faculty in the Social Sciences departments. The papers have not been peer reviewed.  To add your voice to the discussion, please submit your paper to iserp-communication@columbia.edu, or upload it here. Thank you to the faculty who have submitted a working paper for our first bulletin, we are hoping this initiative will tighten the ties of our research community.

To read and download any of these working papers, click on any of the papers, or visit our new site: ISERP's Working Papers. This site is UNI-protected, and only Columbia and Barnard affiliates have access to it.

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Topics covered in this bulletin:

Voting, Democracy, and Government

Networks, Data, and Statistics

War, Extremism, and Violence

Education

Covid-19 and Health

Climate Change

Misinformation, Information, and Communication 

 
Voting, Democracy, and Government

We compare multi-candidate elections under plurality rule versus ranked choice voting (RCV). In our framework candidates choose whether to pursue a narrow campaign that targets their base, or instead pursue a broad campaign that can appeal to the entire electorate. We present two main results comparing RCV to plurality. First, RCV can intensify candidates’ incentives to target their core supporters at the expense of a broader appeal. Second, RCV may increase the probability that a candidate who would lose any pairwise contest nonetheless wins a multi-candidate contest. Our results challenge widely held contentions about the benefits of adopting RCV.

keywords: voting rules, election, ranked choice voting, voter turnout

Liquid Democracy. Two Experiments on Delegation in Voting 
Joseph Campbell, Economics, Alessandra Casella, Economics and Political Science, Lucas de Lara, Economics, Victoria Mooers, Economics, Dilip Ravindran, Economics, Humboldt University of Berlin

Liquid Democracy is a voting system touted as the golden medium between representative and direct democracy: decisions are taken by referendum, but voters can delegate their votes as they wish. The outcome can be superior to simple majority voting, but even when experts are correctly identified, delegation must be used sparely. We ran two very different experiments: one follows a tightly controlled lab design; the second is a perceptual task run online where the precision of information is ambiguous. In both experiments, delegation rates are high, and Liquid Democracy underperforms both universal voting and the simpler option of allowing abstention.

keywords: voting rules, majority voting, information aggregation, laboratory experiments, Condorcet Jury theorem, perceptual experiments

How Democracies Polarize: A Multilevel Perspective
Sihao Huang, Physics, Massachusetts Institute of Technology, Alexander F. Siegenfeld, Center for Constructive Communication, MIT Media Lab, Andrew Gelman, Political Science and Statistics

Democracies employ elections at various scales to select officials at the corresponding levels of administration. The geographic distribution of political opinion, the policy issues delegated to each level, and the multilevel interactions between elections can all greatly impact the makeup of these representative bodies. This perspective is not new: the adoption of federal systems has been motivated by the idea that they possess desirable traits not provided by democracies on a single scale. Yet most existing models of polarization do not capture how nested local and national elections interact with heterogeneous political geographies. We begin by developing a framework to describe the multilevel distribution of opinions and analyze the flow of variance among geographic scales, applying it to historical data in the United States from 1912 to 2020. We describe how unstable elections can arise due to the spatial distribution of opinions and how tradeoffs occur between national and local elections. We also examine multi-dimensional spaces of political opinion, for which we show that a decrease in local salience can constrain the dimensions along which elections occur, preventing a federal system from serving as an effective safeguard against polarization. These analyses, based on the interactions between elections and opinion distributions at various scales, offer insights into how democracies can be strengthened to mitigate polarization and increase electoral representation.

keywords: polarization, political geography, public opinion, federalism

Minority Turnout and Representation under Cumulative Voting. An Experiment.
Alessandra Casella, Economics and Political Science, Jeffrey Da-Ren Guo, Economics, Michelle Jiang, Economics

Under majoritarian election systems, securing the participation and representation of minorities remains an open problem, made salient in the US by its history of voter suppression. One remedy recommended by the courts is the adoption of Cumulative Voting (CV) in multi-member districts: each voter has as many votes as open positions and can cumulate votes on as few candidates as desired. Theory predicts that CV encourages the minority to overcome obstacles to voting: although each voter is treated equally, CV increases minority’s turnout relative to the majority, and the minority’s share of seats won. A lab experiment based on a costly voting design strongly supports both predictions.

key words: voting rules, voter suppression, turnout, minority protection, laboratory experiments

Sequential Veto Bargaining with Incomplete Information
S. Nageeb Ali, Economics, Pennsylvania State University, Navin Kartik, Economics, Andreas Kleiner, Economics, Arizona State University

We study sequential bargaining between a proposer and a veto player. Both have single-peaked preferences, but the proposer is uncertain about the veto player’s ideal point. The proposer cannot commit to future proposals. When players are patient, there can be equilibria with Coasian dynamics: the veto player’s private information can largely nullify proposer’s bargaining power. Our main result, however, is that there are also equilibria in which the proposer obtains the high payoff that he would with commitment power. The driving force is that the veto player’s single peaked preferences give the proposer an option to “leapfrog”, i.e., to secure agreement from only low-surplus types early on to credibly extract surplus from high types later. Methodologically, we exploit the connection between sequential bargaining and static mechanism design.

keywords: theoretical economics, sequential bargaining, Coasian dynamics, veto player
 

Networks, Data, and Statistics 
 

Making a Swap: Network Formation with Increasing Marginal Costs
Evan Sadler, Economics

I propose a simple theory of strategic network formation that accounts for many empirical patterns. Three parts help forge the theory: i) convex linking costs, ii) local linking benefits, and iii) swap-proofness, a new refinement of pairwise stability. If players agree about who is a more desirable neighbor, then a unique swap-proof stable graph generically exists, and stability robustly begets homophily and clustering. With similar assumptions on players’ desire for links, stable graphs take on structures—strong hierarchies or ordered overlapping cliques—that mirror real networks in different domains. Strong hierarchies in particular compel certain patterns in network games with strategic complements, highlighting a mechanism through which status rankings replicate themselves across unrelated contexts. A more general existence theorem unifies several results in the matching literature, and a statistical model to which it applies suggests one approach to preference estimation.

keywords: networks, statistical graphics, homophily 

Identification and Estimation of Causal Peer Effects Using Double Negative Controls for Unmeasured Network Confounding
Naoki Egami, Political Science, Eric J. Tchetgen Tchetgen, Statistics and Data Science, Wharton School, University of Pennsylvania

Scientists have been interested in estimating causal peer effects to understand how people’s behaviors are affected by their network peers. However, it is well known that identification and estimation of causal peer effects are challenging in observational studies for two reasons. The first is the identification challenge due to unmeasured network confounding, for example, homophily bias and contextual confounding. The second issue is network dependence of observations, which one must take into account for valid statistical inference. Negative control variables, also known as placebo variables, have been widely used in observational studies including peer effect analysis over networks, although they have been used primarily for bias detection. In this article, we establish a formal framework which leverages a pair of negative control outcome and exposure variables (double negative controls) to nonparametrically identify causal peer effects in the presence of unmeasured network confounding. We then propose a generalized method of moments estimator for causal peer effects, and establish its consistency and asymptotic normality under an assumption about ψ-network dependence. Finally, we provide a network heteroskedasticity and autocorrelation consistent variance estimator. Our methods are illustrated with an application to peer effects in education.

keywords: causal inference, homophily, interference, networks, peer effects

Quantifying Robustness to External Validity Bias
Martin Devaux, Political Science, Naoki Egami, Political Science

The external validity of experimental results is essential in the social sciences. Existing methods estimate causal effects in a target population, called the target population average treatment effect (T-PATE). However, these methods are sometimes difficult to implement either because it is infeasible to obtain data for the target population or because there is no target population that analysts and skeptics can agree on. We consider a different goal — quantifying how robust an experiment is to external validity bias. In particular, we propose a measure of external robustness by estimating how much different a population should be from the experimental sample to explain away the T-PATE. Large estimated external robustness implies that causal conclusions remain the same unless populations of interest are significantly different from the experimental sample. Unlike the standard generalization approach, estimation of external robustness only requires experimental data and does not require any population data. We prove that the proposed estimator is consistent to the true external robustness under common generalization assumptions and, more importantly, has a simple interpretation even when those assumptions are violated. We provide benchmarks to help interpret the degree of external robustness in each application.

keywords: causal inference, external validity, generalization

Delivering data differently
Gwynn Sturdevant, Laboratory of Innovation Science, Harvard University, A. Jonathan R. Godfrey, Mathematical and Computational Sciences, Massey University, Andrew Gelman, Political Science and Statistics

Human-computer interaction relies on mouse/touchpad, keyboard, and screen, but tools have recently been developed that engage sound, smell, touch, muscular resistance, voice dialogue, balance, and multiple senses at once. How might these improvements impact upon the practice of statistics and data science? People with low vision may be better able to grasp and explore data. More generally, methods developed to enable this have the potential to allow sighted people to use more senses and become better analysts. We would like to adapt some of the wide range of available computer and sensory input/output technologies to transform data science workflows. Here is a vision of what this synthesis might accomplish.

keywords: accessibility, sensification, statistical graphics, visualization, vivification

Causal quartets: Different ways to attain the same average treatment effect
Andrew Gelman, Political Science and Statistics, Lauren Kennedy, Monash University

The average causal effect can often be best understood in the context of its variation. We demonstrate with two sets of four graphs, all of which represent the same average effect but with much different patterns of heterogeneity. As with the famous correlation quartet of Anscombe (1973), these graphs dramatize the way in which real-world variation can be more complex than simple numerical summaries.

keywords: causal inference, average effects, heterogeneous causal effects, experimental design

War, Extremism, and Violence
 

Does Extremism Lead to Terrorism? Rebel Goals and Tactics in Civil Wars
Renanah Miles Joyce, Politics, Brandeis University, Page Fortna, Political Science

Extremism and terrorism are thought to go hand-in-hand in civil wars. Do they? Are rebel groups with more extreme goals more likely than moderate ones to employ terrorism? Understanding the relationship between what groups want and how they try to achieve it has obvious theoretical and policy implications. A common assumption is that extremist groups are more likely than moderate ones to engage in terrorism. Yet arguments linking extremism to terrorism are often circular: groups are tagged as extremist because they do extreme things. Our article addresses this problem by articulating a novel conceptualization of extremism as the distance of group goals from the status quo. We theorize causal mechanisms that might connect extremist goals to terrorism, and use new data on rebel group extremism in civil wars from 1970 to 2013 to examine the empirical relationship between extremism and terrorism in a non-tautological way. The results show that some extremist goals affect terrorism but not others. Groups whose goals involve changing the political ideology of the state or transforming political power across identity groups are more likely to use terrorism or to use more of it. Secessionist groups, however, are no more likely to produce terrorism than are those with less extreme territorial aims such as autonomy.

keywords: terrorism, extremism, rebel tactics, civil war, insurgency, violence against civilians

Education
 

Prestige Seeking in College Application and Major Choice
Yeon-Koo Che, Economics, Dong Woo Hahm, Economics, University of Southern California, Jinwoo Kim, Economics and SIER, Seoul National University, Se-Jik Kim, Economics and SIER, Seoul National University, Olivier Tercieux, Paris School of Economics

We develop a signaling model of prestige seeking in competitive college applications. A prestigious program attracts high-ability applicants, making its admissions more selective, which in turn further increases its prestige, and so on. This amplifying effect results in a program with negligible quality advantage enjoying a significant prestige in equilibrium. Furthermore, applicants “sacrifice” their fits for programs in pursuit of prestige, which results in the misallocation of program fits. Major choice data from Seoul National University provides evidence for our theoretical predictions when majors are assigned through competitive screening—a common feature of college admissions worldwide.

keywords: education, prestige, college admissions, college major choice

Coordinated Markets, School-to-Work Linkages, and Labor Market Outcomes in the European Union
Thomas DiPrete, Sociology, Joanna Chae, Sociology

A large literature has theorized about the importance of skill formation systems for labor market outcomes. Focusing on twenty two European countries, this paper establishes that countries differ in the strength of the pathways that connect educational credentials to the occupational structure. Pathway strength matters for the quality of occupational matching, for employment and earnings, and for the earnings gap between well matched and less well-matched workers. Country differences matter most clearly in their implications for the average strength of linkage between educational credentials and the occupational structure. The strength of the association between local linkage strength and labor market outcomes may also vary by country or across the various country clusters that have been identified in the institutional literature. However, the considerable within-country heterogeneity in the cross-country rankings of individual pathways implies that one needs to look within countries to understand pathway structure and its connection with career progression and labor market outcomes.

keywords: education, labor markets, school to work transitions

Covid-19 and Health
 

Vaccine Diplomacy: How COVID-19 Vaccine Distribution in Latin America Increases Trust in Foreign Governments
Elena Barham, Political Science, Sarah Zukerman Daly, Political Science, Julian E. Gerez, Political Science, John Marshall, Political Science, Oscar Pocasangre, Political Science

Vaccine distribution in the Global South has created opportunities for vaccine-developing countries to improve their international reputations. Leveraging a panel survey conducted in early 2021, we evaluate whether “vaccine diplomacy” affects trust in foreign governments in six Latin American countries. Among vaccinated respondents, we find that trust in the government of the country that they believed developed their vaccine increased relative to trust in the governments of other foreign powers. Furthermore, providing information about the aggregate distribution of vaccines within a respondent’s country increased vaccine-eligible respondents’ trust in the governments of countries from which more vaccines were delivered. In each case, greater trust principally reflects updated perceptions of a common good motivation. Our empirical findings suggest that vaccine distribution—especially for China, but for other vaccine-developing countries as well—can cultivate favorable international public opinion. This may in turn facilitate great powers’ economic, political, or military foreign policy goals.

keywords: covid-19 policy, vaccine diplomacy, public trust, Global South
 

Climate Change
 

Climate Change and Transfers: A Coase Theorem
Prajit Kumar Dutta, Economics, Roy Radner, Business, New York University

Climate-related payments - paying developing countries for damages have emerged as the single-most contentious and complex of all issues in climate negotiations. After thirty years of discussion, they were accepted by developed countries in the last round of negotiations at Sharm-El-Sheikh in November, 2022. Yet, major questions remain on how this will be done and how effective payments will be. The paper studies transfers under a variety of timing possibilities. It is shown that outcome-contingent payments always lead to efficiency and a particular alignment of transfer and emission timings leads to that efficient equilibrium being the only equilibrium even when the horizon is infinite. The theoretical novelty is a multi-lateral Coase Theorem in a dynamic model. The policy prescription is for an enhanced role for transfers to solve the climate problem.

keywords: Coase Theorum, climate change, efficient equilibrium 
 

Misinformation, Information, and Communication
 

Sustained exposure to fact-checks can inoculate citizens against misinformation
Jeremy Bowles, King Center on Global Development, Kevin Croke, Public Health, Harvard University, Horacio Larreguy, Economics and Political Science, ITAM, Shelley Liu, Public Policy, UC Berkeley, John Marshall, Political Science

We evaluate whether sustained exposure to fact-checks reduces citizens’ susceptibility to misinformation and, in turn, promotes accurate beliefs that guide informed behaviors. In partnership with a major fact-checking organization in South Africa, we evaluated a six-month intervention that incentivized individuals to consume biweekly fact-checks delivered via WhatsApp. Experimental estimates show that the intervention increased participants’ capacity to discern true from false news and doubt conspiracy theories, and reduced their propensity to share social media posts. In line with inoculation theories, sustained access to fact-checks increased awareness of how to verify information and reduced trust in social media content, but had little effect on reported media consumption behaviors or active efforts to verify information. Our post-intervention surveys suggest that some modes of regular fact-check delivery shifted attitudes and behaviors connected to common targets of misinformation: these treated participants reported taking more precautions against COVID-19 and increased their trust in, and appraisal of, their government. Leveraging variation in the mode of delivery, we find that the results are primarily driven by treatment variants that delivered fact-checks as a text message or an empathetic podcast. These findings show that sustained and scalable fact-checks can inoculate citizens upon exposure to misinformation and reduce its spread, while also highlighting the difficulties of changing citizens’ consumption and verification behaviors.

keywords: fact-checking organizations, misinformation spread, public attitude, social media 

Beyond Unbounded Beliefs: How Preferences and Information Interplay in Social Learning
Navin Kartik, Economics, SangMok Lee, Economics, Washington University in St. Louis, Tianhao Liu, Economics, Daniel Rapaport, Booth School of Business, University of Chicago

When does society eventually learn the truth, or take the correct action, via observational learning? In a general model of sequential learning over social networks, we identify a simple sufficient—and, in a sense, necessary—condition for learning dubbed excludability. Excludability is a joint property of agents’ preferences and their information. When required to hold for all preferences, it is equivalent to information having “unbounded beliefs”, which demands that any agent can individually identify the truth, even if only with small probability. But unbounded beliefs may be untenable with more than two states: e.g., it is incompatible with the monotone likelihood ratio property. Excludability reveals that what is crucial for learning, instead, is that a single agent must be able to rule out any wrong action, even if she cannot take the correct action. Consequently, excludability helps study classes of preferences and information that mutually ensure learning. We develop two such pairs: (i) for a one-dimensional state, preferences with single-crossing differences and a new informational condition, directionally unbounded beliefs; and (ii) for a multi-dimensional state, Euclidean preferences and subexponential location-shift information.

keywords: social learning, herds, information, cascades, single crossing, Euclidean preferences, unbounded beliefs

Single-Crossing Differences in Convex Environments
Navin Kartik, Economics, SangMok Lee, Economics, Washington University in St. Louis, Daniel Rappoport, Booth School of Business, University of Chicago

An agent’s preferences depend on an ordered parameter or type. We characterize the set of utility functions with single crossing differences (SCD) in convex environments. These include preferences over lotteries, both in expected utility and rank-dependent utility frameworks, and preferences over bundles of goods and over consumption streams. Our notion of SCD does not presume an order on the choice space. This unordered SCD is necessary and sufficient for “interval choice” comparative statics. We present applications to cheap talk, observational learning, and collective choice, showing how convex environments arise in these problems and how SCD/interval choice are useful. Methodologically, our main characterization stems from a result on linear aggregations of single-crossing functions.

keywords: single crossing differences, observational learning, monotone comparative statics, choice among lotteries, interval equilibria, aggregating single crossing

Mediating Conflict in the Lab
Alessandra Casella, Economics and Political Science, Evan Friedman, Economics, Paris School of Economics, Manuel Perez Archila, Economics, Princeton University

Mediation of disputes is increasingly common, and computer-run algorithms are taking a central role. We test the efficacy of a theoretically optimal mediation algorithm in an experiment where two subjects negotiate how to share a resource. The subjects send cheap talk messages to one another (under direct communication) or to the computer mediator (under mediation), before expressing demands or receiving the mediator’s recommendation. While messages to the computer mediator are more sincere, peaceful resolution is not more frequent. We argue, theoretically and experimentally, that exactly when it is most promising, the mechanism is fragile to any deviation from full sincerity.

keywords: mediation, conflict resolution, mechanism design, cheap talk, laboratory experiments 

To read and download any of these working papers, click on any of the papers, or visit our new site: ISERP's Working Papers. This site is UNI-protected, and only Columbia and Barnard affiliates have access to it.

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