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11. Outliers in semi-parametric Estimation of Treatment Effects

Author:
Darwin Ugarte Ontiveros, Gustavo Canavire-Bacarreza, and Luis Castro Peñarrieta
Publication Date:
10-2017
Content Type:
Working Paper
Institution:
Institute for Advanced Development Studies (INESAD)
Abstract:
Average treatment effects estimands can present significant bias under the presence of outliers. Moreover, outliers can be particularly hard to detect, creating bias and inconsistency in the semi-parametric ATE estimads. In this paper, we use Monte Carlo simulations to demonstrate that semi-parametric methods, such as matching, are biased in the presence of outliers. Bad and good leverage points outliers are considered. The bias arises because bad leverage points completely change the distribution of the metrics used to define counterfactuals. Whereas good leverage points increase the chance of breaking the common support condition and distort the balance of the covariates and which may push practitioners to misspecify the propensity score. We provide some clues to diagnose the presence of outliers and propose a reweighting estimator that is robust against outliers based on the Stahel-Donoho multivariate estimator of scale and location. An application of this estimator to LaLonde’s (1986) data allows us to explain the Dehejia and Wahba (2002) and Smith and Todd (2005) debate on the inability of matching estimators to deal with the evaluation problem.
Topic:
Economics, Econometrics, Methods, and Counterfactuals
Political Geography:
Global

12. Sports Heroes and Mass Sports Participation – The (Double) Paradox of the “German Tennis Boom”

Author:
Arne Feddersen, Sven Jacobsen, and Wolfgang Maennig
Publication Date:
11-2009
Content Type:
Working Paper
Institution:
Chair for Economic Policy, University of Hamburg
Abstract:
The major sporting success of one’s countrymen and women is often supposed to promote the growth of general participation in that sport. This study is the first to analyse the impact of sports heroes on the membership figures of the corresponding sports association by means of an econometric analysis. We do so by evaluating the so-called "Boris Becker effect" by simultaneously testing for the effects of the rise and retirement of the three stars Boris Becker, Stefanie Graf, and Michael Stich. As a first paradox, our results indicate a negative tennis growth effect associated with the time period of the ascendency of the sport stars. With the first paradox, their retirement should then have a positive effect. In this sense, our second result of a statistically negative tennis growth since the declining success of the German tennis stars must be regarded as a second paradox.
Topic:
Sports, Participation, Econometrics, and Tennis
Political Geography:
Europe and Germany

13. Modeling Amazon Deforestation for Policy Purposes

Author:
Clive W. J. Granger and Lykke E. Andersen
Publication Date:
10-2006
Content Type:
Working Paper
Institution:
Institute for Advanced Development Studies (INESAD)
Abstract:
Brazil has long ago removed most of the perverse government incentives that stimulated massive deforestation in the Amazon in the 70s and 80s, but one highly controversial policy remains: Road building. While data is now abundantly available due to the constant satellite surveillance of the Amazon, the analytical methods typically used to analyze the impact of roads on natural vegetation cover are methodologically weak and not very helpful to guide public policy. This paper discusses the respective weaknesses of typical GIS analysis and typical municipality level regression analysis, and shows what would be needed to construct an ideal model of deforestation processes. It also presents an alternative approach that is much less demanding in terms of modeling and estimation and more useful for policy makers as well.
Topic:
Environment, Infrastructure, Econometrics, and Deforestation
Political Geography:
Brazil and Amazon Basin