Confidence Intervals for Bias and Size Distortion in IV and Local Projections-IV Models

Publication in “Journal of Business & Economic Statistics” by
Gergely Ganics ’12 (with A. Inoue and B. Rossi)


In this article, we propose methods to construct confidence intervals for the bias of the two-stage least squares estimator, and the size distortion of the associated Wald test in instrumental variables models with heteroscedasticity and serial correlation. Importantly our framework covers the local projections—instrumental variable model as well. Unlike tests for weak instruments, whose distributions are nonstandard and depend on nuisance parameters that cannot be consistently estimated, the confidence intervals for the strength of identification are straightforward and computationally easy to calculate, as they are obtained from inverting a chi-squared distribution. Furthermore, they provide more information to researchers on instrument strength than the binary decision offered by tests. Monte Carlo simulations show that the confidence intervals have good, albeit conservative, in some cases, small sample coverage. We illustrate the usefulness of the proposed methods in two empirical situations: the estimation of the intertemporal elasticity of substitution in a linearized Euler equation, and government spending multipliers. 

Supplementary materials for this article are available online. The online appendix contains the proofs, further theoretical and Monte Carlo results, and the description of the datasets used in the present article. Replication code is available on the journal’s website.

Measuring horizontal inequity in healthcare utilisation

Publication by Mohammad Habibullah Pulok ’12 (HEP)

My first paper from PhD is out in the European Journal of Health Economics: “Measuring horizontal inequity in healthcare utilisation: a review of methodological developments and debates”

Paper abstract

Equity in healthcare is an overarching goal of many healthcare systems around the world. Empirical studies of equity in healthcare utilisation primarily rely on the horizontal inequity (HI) approach which measures unequal utilisation of healthcare services by socioeconomic status (SES) for equal medical need. The HI method examines, quantifies, and explains inequity which is based on regression analysis, the concentration index, and the decomposition technique. However, this method is not beyond limitations and criticisms, and it has been subject to several methodological challenges in the past decade.

This review presents a summary of the recent developments and debates on various methodological issues and their implications on the assessment of HI in healthcare utilisation. We discuss the key disputes centred on measurement scale of healthcare variables as well as the evolution of the decomposition technique. We also highlight the issues about the choice of variables as the indicator of SES in measuring inequity. This follows a discussion on the application of the longitudinal method and use of administrative data to quantify inequity.

Future research could exploit the potential for health administrative data linked to social data to generate more comprehensive estimates of inequity across the healthcare continuum. This review would be helpful to guide future applied research to examine inequity in healthcare utilisation.

About the author


Mohammad Habibullah Pulok ’12 is a post-doc researcher at Dalhousie University in Canada. He is an alum of the Barcelona GSE Master’s in Health Economics and Policy (now EPP).

How Destructive is Innovation?

Publication in Econometrica by Daniel Garcia-Macia ’11 (Economics)

cover image

Daniel’s paper “How Destructive is Innovation?” (with Chang-Tai Hsieh & Peter Klenow) has been published in Econometrica (September 2019).

The paper has received media attention in NBER Digest, Chicago Booth Review, Financial Times, and Bloomberg.

Paper abstract

Entrants and incumbents can create new products and displace the products of competitors. Incumbents can also improve their existing products. How much of aggregate productivity growth occurs through each of these channels? Using data from the U.S. Longitudinal Business Database on all nonfarm private businesses from 1983 to 2013, we arrive at three main conclusions: First, most growth appears to come from incumbents. We infer this from the modest employment share of entering firms (defined as those less than 5 years old). Second, most growth seems to occur through improvements of existing varieties rather than creation of brand new varieties. Third, own‐product improvements by incumbents appear to be more important than creative destruction. We infer this because the distribution of job creation and destruction has thinner tails than implied by a model with a dominant role for creative destruction.

Daniel Garcia-Macia ’11 (PhD, Stanford University) is an Economist at the International Monetary Fund. He is an alum of the Barcelona GSE Master’s in Economics.

Small Numbers, Big Concerns: Practices and Organizational Arrangements in Rare Disease Drug Repurposing

Publication by Burcu Kucukkeles ’12 (Economics)

Burcu Kücükkeles (Economics ’12) has published a paper in the Academy of Management Discoveries. In this paper, “Small Numbers, Big Concerns: Practices and Organizational Arrangements in Rare Disease Drug Repurposing,” Burcu and her colleagues looked into the societal challenge of developing drugs for rare diseases (a rare disease is a condition that affects less than 200,000 people in the United States or 1 in 2,000 people in the European Union).

By studying the market and government failures in rare diseases and practices of two nonprofit organizations, Burcu and her colleagues contribute to the Agenda on the Sustainable Development Goals beyond the implications of their study to the management literature.

Burcu is currently a PhD candidate at the Chair of Strategic Management and Innovation, Department of Management, Technology, and Economics, ETH Zurich. Voice readers are welcome to email her for access to the full paper or with any questions about this research: burcuk [ at ] ethz [. ]ch

Paper Abstract

Due to their small market size, many rare diseases lack treatments. While government incentives exist for the development of drugs for rare diseases, these interventions have yielded insufficient progress. Drawing on an in-depth case study of rare diseases therapies, we explore how the practices of two nonprofit organizations allowed them to circumvent the endemic market and government failures involving positive externalities by using generic drug repurposing—i.e., seeking new therapeutic applications for existing generic drugs. Beyond elucidating the potential of generic drug repurposing for those suffering from rare diseases, our discoveries provide important insights into the mutual constitution of organizational arrangements for societal challenges and the practices they host. By showing how organizational arrangements can both reinforce and extend practices such that they enable practitioners to achieve a standard of excellence, our study advances practice theory and research on the comparative efficacy of alternative organizational arrangements for tackling societal challenges.


Burcu Kucukkeles ’12 is PhD Candidate at ETH Zurich and an alum of the Barcelona GSE Master’s in Economics.

How do firms adjust to rises in the minimum wage? Survey evidence from Central and Eastern Europe

Publication by Nataša T. Jemec ’09 (Economics) and Ludmila Fadejeva ’11 (Macro)

Nataša Todorović Jemec ’09 (Economics) and Ludmila Fadejeva ’11 (Macroeconomic Policy and Financial Markets) have published a paper in the IZA Journal of Labour Policy, together with a few other colleagues from central banks of new EU member states. The paper, “How do firms adjust to rises in the minimum wage? Survey evidence from Central and Eastern Europe,” studies the transmission channels for rises in the minimum wage using a unique firm-level dataset from eight Central and Eastern European countries.

They wrote the publication within the ECB Wage Dynamics Network (WDN). At the time, Nataša and Ludmila were working at the Central Bank of Slovenia and the Central Bank of Latvia respectively, and they were their banks’ representatives in the WDN. Increase of the minimum wage was a common topic of many new EU members, and they decided to write a paper on that based on the data that they collected through a WDN survey in their countries.

Researchers can use this form to request access to the data of the WDN network which includes many EU countries.

Paper abstract

We study the transmission channels for rises in the minimum wage using a unique firm-level dataset from eight Central and Eastern European countries. Representative samples of firms in each country were asked to evaluate the relevance of a wide range of adjustment channels following specific instances of rises in the minimum wage during the recent post-crisis period. The paper adds to the rest of literature by presenting the reactions of firms as a combination of strategies and evaluates the relative importance of those strategies. Our findings suggest that the most popular adjustment channels are cuts in non-labour costs, rises in product prices, and improvements in productivity. Cuts in employment are less popular and occur mostly through reduced hiring rather than direct layoffs. Our study also provides evidence of potential spillover effects that rises in the minimum wage can have on firms without minimum wage workers.

About the authors

Nataša T. Jemec ’09 is a Senior Economist at IMAD. She is an alum of the Barcelona GSE Master’s in Economics.

Ludmila Fadejeva ’11 is a Senior Econometrician at the Bank of Latvia. She is an alum of the Barcelona GSE Master’s in Macroeconomic Policy and Financial Markets.

Bank Assets, Liquidity and Credit Cycles

Forthcoming publication by Federico Lubello ’12 (Economics)

My paper, “Bank Assets, Liquidity and Credit Cycles” with Ivan Petrella (Warwick and CEPR) and Emiliano Santoro (University of Copenhagen) has been accepted at the Journal of Economic Dynamics and Control. In the paper, we uncover a close connection between the collateralization of bank loans, macroeconomic amplification and the degree of procyclicality of bank leverage.


We study how bank collateral assets and their pledgeability affect the amplitude of credit cycles. To this end, we develop a tractable model where bankers intermediate funds between savers and borrowers. If bankers default, savers acquire the right to liquidate bankers’ assets. However, due to the vertically integrated structure of our credit economy, savers anticipate that liquidating financial assets (i.e., loans) is conditional on borrowers being solvent on their debt obligations. This friction limits the collateralization of bankers’ financial assets beyond that of real assets (i.e., capital). In this context, increasing the pledgeability of financial assets eases more credit and reduces the spread between the loan and the deposit rate, thus attenuating capital misallocation as it typically emerges in credit economies à la Kiyotaki and Moore (1997). We uncover a close connection between the collateralization of bank loans, macroeconomic amplification and the degree of procyclicality of bank leverage.

Federico Lubello ’12 is a Research Economist at Banque centrale du Luxembourg. He is an alum of the Barcelona GSE Master’s in Economics.


City Design, Planning, Policy Innovations: The Case of Hermosillo

IDB publication co-authored by Miguel Angel Santos (ITFD ’11, Economics ’12)

credit: IDB

After a lengthy review process we are proud to announce that our book “City Design, Planning, Policy Innovations: The Case of Hermosillo” is published and available for download from the Inter-American Development Bank. Cutting edge research on cities featuring my work with Douglas Barrios, my colleague at the Center for International Development’s Growth Lab at the Harvard Kennedy School. Thanks to Andreina Seijas and Diego Arcia for the superb coordination and editing work.

About the book

This publication summarizes the outcomes and lessons learned from the Fall 2017 course titled “Emergent Urbanism: Planning and Design Visions for the City of Hermosillo, Mexico” (ADV-9146). Taught by professors Diane Davis and Felipe Vera, this course asked a group of 12 students to design a set of projects that could lay the groundwork for a sustainable future for the city of Hermosillo—an emerging city located in northwest Mexico and the capital of the state of Sonora. Part of a larger initiative funded by the Inter-American Development Bank and the North-American Development Bank in partnership with Harvard University, ideas developed for this class were the product of collaboration between faculty and students at the Graduate School of Design, the Kennedy School’s Center for International Development and the T.H. Chan School of Public Health.

Miguel Angel Santos (ITFD ’11, Economics ’12) is Director of Applied Research at the Growth Lab at Harvard Kennedy School.

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The Zero Lower Bound was irrelevant

Blog post for AIER by Brian C. Albrecht ’14 (Economics of Public Policy)

empty building floor

Brian Albrecht is a PhD candidate at the University of Minnesota and a graduate of the Barcelona GSE Master’s Program in Economics of Public Policy, as well as a past editor of the Barcelona GSE Voice. He is also a contributor to the Sound Money Project, a blog from the American Institute for Economic Research (AIER).

In a recent post, Brian talks about a recent paper by Barcelona GSE professors Davide Debortoli, Jordi Galí, and Luca Gambetti, “On the Empirical (Ir)Relevance of the Zero Lower Bound Constraint.” He writes:

Many economics writers, including Ben BernankeNeil Irwin, and Justin Wolfers, worry that the Fed will not be able to combat the next recession. Current interest rates, the sad story goes, are already close to zero. Since a downturn will push the economy to the zero lower bound (ZLB), the Fed will not be able to lower rates further, thereby prolonging the recession.

Of course, for such a story to make sense, the ZLB must be a fundamental constraint that inhibits monetary policy. In a new NBER working paper, Davide Debortoli, Jordi Galí, and Luca Gambetti consider whether the ZLB was actually the problem during the last recession. They say the ZLB was irrelevant. The authors come to this conclusion by studying two types of evidence: measures of macro volatility, and the response of macro variables to aggregate shocks through a vector autoregression.

Brian C. Albrecht for Sound Money

Read Brian’s full post on this paper and find a list of all his recent posts over on the AIER website.


Brian C. Albrecht ’14 is a PhD candidate in Economics at the University of Minnesota. He is an alum of the Barcelona GSE Master’s in Economics of Public Policy.

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Asymmetric Social Distance Effects in the Ultimatum Game

Publication by Orestis Vravosinos ’18 (Economics) with Kyriakos Konstantinou

The Ultimatum Game Comic
Comic author: Zach Weinersmith

A paper by Orestis Vravosinos (Economics ’18, UPF MRes in Economics ’19) and Kyriakos Konstantinou (LSE) has just been published in the Review of Behavioral Economics. Below is an overview of the paper.

The Ultimatum Game

Given that in experiments ultimatum game outcomes are often significantly different from Nash equilibrium predictions under standard assumptions on preferences, many studies have examined the impact of fairness on players’ considerations and how the effect of the sense of fairness on players’ actions may vary, while other factors change. It has been argued that increased stakes (larger sum of money distributed) can reduce sensitivity to fairness of player 2 making it more likely that she accepts lower shares of the total sum, thus, giving player 1 the opportunity to offer a lower share.

Social Distance

Social distance has also been found to affect fairness. In the existing literature, social distance commonly varies only from players being close relatives or friends to complete strangers, even though negatively-valenced relationships can be important from an economic point of view. Our study aims to fill this gap by introducing negatively-valenced relationships between the players. We argue that altruistic and empathetic behavior of the proposer towards the responder may not vary (increase) as significantly in the region of negative relationships compared to the region of positive relationships. Similarly, social distance effects stemming from reciprocity may vary less in the region of negative relationships. Thus, we hypothesize that in the ultimatum game social distance effects are asymmetric with their magnitude varying more in the spectrum of positively compared to negatively-valenced relationships.

Our experimental results support this hypothesis; in the region of positively-valenced relationships, the proposers increase the percentage they offer as relationship quality increases more drastically compared to when the relationship is negatively-valenced, in which case they appear more invariant to relationship effects. Also, by eliciting a minimum share which the responder is willing to accept out of the total sum, we provide clearer results on the social distance and stakes effects on the latter’s behavior. Last, we find a negative effect of relationship quality on the minimum acceptable share. This contradicts a strand of the literature which suggests that closer-“in-group” individuals may be punished more severely, so that cooperation in a group is maintained.


Orestis Vravosinos and Kyriakos Konstantinou (2019), “Asymmetric Social Distance Effects in the Ultimatum Game”, Review of Behavioral Economics: Vol. 6: No. 2, pp 159-192.

Orestis Vravosinos

Orestis Vravosinos ’18 is an MRes student at GPEFM (UPF and Barcelona GSE). He is an alum of the Barcelona GSE Master’s in Economics.

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The Transition to the Knowledge Economy, Labor Market Institutions, and Income Inequality in Advanced Democracies

Publication by Angelo Martelli ’11 (Economics)

Angelo Martelli '11

Hot off the press! My publication “The Transition to the Knowledge Economy, Labor Market Institutions, and Income Inequality in Advanced Democracies” with David Hope (King’s College) is finally out in World Politics.

A good read for all those interested in understanding the extent to which the relationship between the changing nature of work and income inequality is influenced by national labor market institutions.

Paper abstract

Recent work in comparative political economy has found that labour market institutions can mitigate the inequality-enhancing effects of the transition to the knowledge economy (Hope and Martelli 2019). While this work enhances our understanding of the role and importance of labour market institutions in the post-industrial era, it cannot tell us much about the underlying mechanisms. This paper aims to fill that gap in the literature by undertaking a micro-level econometric study on Denmark using a unique longitudinal dataset with linked employer-employee data, the Integrated Database for Labour Market Research (IDA). The central analysis in the paper will explore the influence of union membership and collective bargaining on within and between firm inequality in knowledge-intensive sectors. It will also test competing hypotheses as to why labour market institutions have been able to damp down the effects of the transition to the knowledge economy on income inequality.

A couple of takeaways

The transition to the knowledge economy began in earnest after the crisis of Fordism in the 1970s. Figure 1 (below) shows the employment expansion in knowledge-intensive service sectors, such as finance, insurance, business services, and telecommunications, between 1970 and 2006. Growth of knowledge employment was ubiquitous in the advanced democracies over this period; the average employment expansion was close to nine percentage points. The rise of the knowledge economy is clearly demonstrated by this substantial shift in economic structure away from traditional industries and toward ICT-intensive service sectors.

figure 1

Figure 2 (below) shows that for the income share of the top 1 percent, an increase in knowledge employment is associated with an increase in inequality when wage coordination and collective bargaining coverage are very weak, but has little or no effect when they’re at their highest levels.

figure 2

You can read more about this research in a blog post I wrote with my coauthor based on a previous version of the paper on LSE’s European Politics and Policy blog (EUROPP).

Next we are planning to work on A Micro-Level Study of the Knowledge Economy, Institutions, and Income Inequality.


Angelo Martelli ’11 is a Postdoctoral Research Fellow at LSE. He is an alum of the Barcelona GSE Master’s in Economics.

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