Working papers

This paper presents a simple method for carrying out inference in a wide variety of possibly nonlinear IV models under weak assumptions.

This article explains the usefulness and limitations of the bootstrap in contexts of interest in econometrics.

We consider many structural objects of interest, such as average or quantile treatment effects. We illustrate our results with an empirical application to Engel curve estimation.

Shape constraints play an increasingly prominent role in nonparametric function estimation. While considerable recent attention has been focused on log concavity as a regularizing device in nonparametric density estimation, weaker forms of concavity constraints encompassing larger classes of densities have received less attention but offer some additional flexibility.

In this paper, we describe how to test for the presence of measurement error in explanatory variables. First, we discuss the test of such hypotheses in parametric models such as linear regressions and then introduce a new Stata command [R] dgmtest for a nonparametric test proposed in Wilhelm (2018b).

We propose a new specification test for assessing the validity of fuzzy regression discontinuity designs (FRD-validity). We derive a new set of testable implications, characterized by a set of inequality restrictions on the joint distribution of observed outcomes and treatment status at the cut-off. We show that this new characterization exploits all the information in the data useful for detecting violations of FRD-validity.

In a new CSAE working paper, IFS researcher Dr Rachel Cassidy uses a randomised controlled trial to examine the link between intra-household bargaining and use of new contraceptive technologies in Mozambique.

Do households value access to free health insurance when making labor supply decisions? We answer this question using the introduction of universal health insurance in Mexico, the Seguro Popular (SP), in 2002.

Many time-series exhibit “long memory”: Their autocorrelation function decays slowly with lag. This behavior has traditionally been modeled via unit roots or fractional Brownian motion and explained via aggregation of heterogenous processes, nonlinearity, learning dynamics, regime switching or structural breaks. This paper identifies a different and complementary mechanism for long memory generation by showing that it can naturally arise when a large number of simple linear homogenous economic subsystems with short memory are interconnected to form a network such that the outputs of the subsystems are fed into the inputs of others.

A “patent box” is a term for the application of a lower corporate tax rate to the income derived from the ownership of patents. This tax subsidy instrument has been introduced in a number of countries since 2000. Using comprehensive data on patent filings at the European Patent Office, including information on ownership transfers pre‐ and post‐grant, we investigate the impact of the introduction of a patent box on international patent transfers, on the choice of ownership location, and on invention in the relevant country.

This article introduces and investigates the properties of a new bootstrap method for time-series data, the kernel block bootstrap.

Given additional distributional information in the form of moment restrictions, kernel density and distribution function estimators with implied generalised empirical likelihood probabilities as weights achieve a reduction in variance due to the systematic use of this extra information.

This paper shows how to increase the power of Hausman’s (1978) specification test as well as the difference test in a large class of models.

This paper proposes a simple nonparametric test of the hypothesis of no measurement error in explanatory variables and of the hypothesis that measurement error, if there is any, does not distort a given object of interest. We show that, under weak assumptions, both of these hypotheses are equivalent to certain restrictions on the joint distribution of an observable outcome and two observable variables that are related to the latent explanatory variable.

This paper considers inference on fixed effects in a linear regression model estimated from network data.

We investigate partial insurance and group risk sharing in extended family networks.

This chapter sets out the extension of the scope of the classical IV model to cases in which unobserved variables are set-valued functions of observed variables.

This paper examines the equilibrium effects of alternative financial aid policies intended to promote college participation. We build an overlapping generations life cycle model with education, labor supply, and consumption/saving decisions.

We examine the channels through which a randomized early childhood intervention in Colombia led to signicant gains in cognitive and socio-emotional skills among a sample of disadvantaged children aged 12 to 24 months at baseline.

We examine the labor market consequences of an exogenous increase in the supply of skilled labor in several cities in Norway, resulting from the construction of new colleges in the 1970s.