Professor Sokbae (Simon) Lee: all content

Showing 1 – 20 of 113 results

Working paper cover

Identifying the effect of persuasion

Working Paper
This paper examines a commonly used measure of persuasion whose precise interpretation has been obscure in the literature.

14 December 2022

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Institutions, competitiveness and cognitive ability

Working Paper

We investigate whether growing up in a socialist country affects the development of competitiveness by comparing three Korean groups in South Korea, born and raised in three countries with distinct institutional environments: South Korea, North Korea, and China.

24 June 2020

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A tale of two Koreas: Property rights and fairness

Journal article

We compare two groups of the non-student Korean population—native-born South Koreans (SK) and North Korean refugees (NK)—with contrasting institutional and cultural backgrounds. In our experiment, the subjects play dictator games under three different treatments in which the income source varies: first, the income is randomly given to the subject; second, it is earned by the subject; third, it is individually earned by the subject and an anonymous partner and then pooled together.

1 February 2020

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Identifying the effect of persuasion

Working Paper

We set up an econometric model of persuasion and study identification of key parameters under various scenarios of data availability.

9 December 2019

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A tale of two Koreas: property rights and fairness

Working Paper

We compare two groups of the non-student Korean population—native-born South Koreans (SK) and North Korean refugees (NK)—with contrasting institutional and cultural backgrounds.

9 December 2019

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Non-asymptotic inference in a class of optimization problems

Working Paper

This paper describes a method for carrying out non-asymptotic inference on partially identifi ed parameters that are solutions to a class of optimization problems. The optimization problems arise in applications in which grouped data are used for estimation of a model's structural parameters. The parameters are characterized by restrictions that involve the population means of observed random variables in addition to the structural parameters of interest. Inference consists of finding con fidence intervals for the structural parameters. Our method is non-asymptotic in the sense that it provides a fi nite-sample bound on the difference between the true and nominal probabilities with which a confi dence interval contains the true but unknown value of a parameter. We contrast our method with an alternative non-asymptotic method based on the median-of-means estimator of Minsker (2015). The results of Monte Carlo experiments and an empirical example illustrate the usefulness of our method.

17 May 2019

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Optimal Data Collection for Randomized Control Trials

Working Paper

In a randomized control trial, the precision of an average treatment effect estimator and the power of the corresponding t-test can be improved either by collecting data on additional individuals, or by collecting additional covariates that predict the outcome variable. To design the experiment, a researcher needs to solve this tradeoff subject to her budget constraint. We show that this optimization problem is equivalent to optimally predicting outcomes by the covariates, which in turn can be solved using existing machine learning techniques using pre-experimental data such as other similar studies, a census, or a household survey. In two empirical applications, we show that our procedure can lead to reductions of up to 58% in the costs of data collection, or improvements of the same magnitude in the precision of the treatment effect estimator.

2 May 2019

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Identifying effects of multivalued treatments

Working Paper

Multivalued treatment models have typically been studied under restrictive assumptions: ordered choice, and more recently unordered monotonicity. We show how treatment e ects can be identi ed in a more general class of models that allows for multidimensional unobserved heterogeneity.

12 June 2018

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Identifying the effect of persuasion

Working Paper

We set up an econometric model of persuasion and study identification of key parameters under various scenarios of data availability.

19 March 2018

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Testing for a debt-threshold effect on output growth

Journal article

Using the Reinhart–Rogoff dataset, we find a debt threshold not around 90 per cent but around 30 per cent, above which the median real gross domestic product (GDP) growth falls abruptly.

11 December 2017