Research on Microeconometrics: Identification, inference and applications (ROMIA)

Showing 1 - 12 of 16 results

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Testing for a general class of functional inequalities

Journal article

In this article, we propose a general method for testing inequality restrictions on nonparametric functions. Our framework includes many nonparametric testing problems in a unified framework, with a number of possible applications in auction models, game theoretic models, wage inequality, and revealed preferences.

1 December 2017

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Nonparametric estimation and inference under shape restrictions

Journal article

Economic theory often provides shape restrictions on functions of interest in applications, such as monotonicity, convexity, non-increasing (non-decreasing) returns to scale, or the Slutsky inequality of consumer theory; but economic theory does not provide finite-dimensional parametric models. This motivates nonparametric estimation under shape restrictions. Nonparametric estimates are often very noisy. Shape restrictions stabilize nonparametric estimates without imposing arbitrary restrictions, such as additivity or a single-index structure, that may be inconsistent with economic theory and the data. This paper explains how to estimate and obtain an asymptotic uniform confidence band for a conditional mean function under possibly nonlinear shape restrictions, such as the Slutsky inequality. The results of Monte Carlo experiments illustrate the finite-sample performance of the method, and an empirical example illustrates its use in an application.

18 August 2017

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Fixed-effect regressions on network data

Working Paper

This paper studies inference on fixed effects in a linear regression model estimated from network data. An important special case of our setup is the two-way regression model, which is a workhorse method in the analysis of matched data sets. Networks are typically quite sparse and it is difficult to see how the data carry information about certain parameters. We derive bounds on the variance of the fixed-effect estimator that uncover the importance of the structure of the network. These bounds depend on the smallest non-zero eigenvalue of the (normalized) Laplacian of the network and on the degree structure of the network. The Laplacian is a matrix that describes the network and its smallest non-zero eigenvalue is a measure of connectivity, with smaller values indicating less-connected networks. These bounds yield conditions for consistent estimation and convergence rates, and allow to evaluate the accuracy of first-order approximations to the variance of the fixed-effect estimator. The bounds are also used to assess the bias and variance of estimators of moments of the fixed effects.

30 May 2017

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Estimating the production function for human capital: results from a randomized controlled trial in Colombia

Working Paper

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 estimate the determinants of material and time investments in these children and evaluate the im- pact of the treatment on such investments. We then estimate the production functions for cognitive and socio-emotional skills. The e ects of the program can be explained by increases in parental investments, which have strong e ects on outcomes and are complementary to both maternal skills and child's baseline skills.

27 April 2017

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Recombinant innovation and the boundaries of the firm

Journal article

We want to understand how important market frictions are in stifling the transmission of ideas from one firm to another. We use comprehensive data on patent applications from the European Patent Office and a multiple spells duration model to provide estimates that suggest that they are substantial.

1 January 2017