2014

David Deming (Harvard) - The Value of Postsecondary Credentials in the Labor Market: An Experimental Study Wednesday, December 3, 2014

Abstract- We study employers’ perceptions of postsecondary degrees using a field experiment. We randomly assign the sector and selectivity of institution to fictitious resumes and send them to real vacancy postings on a large online job board. According to our results, a bachelor’s degree in business from a for-profit “online” institution is 22 percent less likely to receive a callback than a similar degree from a non-selective public institution. Degrees from selective public institutions are relatively more likely to receive...

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Yaron Singer (Harvard) - Ceci n'est pas un #ad: Detection and Analysis of Covert Ads in Social Media Wednesday, November 12, 2014

Authors- Based on joint work with Jean Pouget-Abadie, Stuart Shieber, Oren Tsur, and Sam Wiseman

Abstract- In online social networks such as Facebook or Twitter users can advertise products and services by using appropriate labels to convey the content they publish is sponsored.  A growing concern is that many users intentionally conceal the commercial intent behind the promotions they publish, disguising them as authentic...

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Devin Caughey (MIT) - Bayesian Population Interpolation and Lasso-Based Target Selection in Survey Weighting Wednesday, November 5, 2014:

Abstract:  We propose solutions to two important problems that have received relatively little attention in the field of survey weighting: the construction of population targets in the face of irregularly missing data, and the optimal selection of weighting targets from the set of possible auxiliary variables. Our solution to the first problem relies on a dynamic Bayesian population-interpolation model that allows subpopulation estimates in a given year to be informed by data from other years. To address the second, we formulate...

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Margaret McConnell (Harvard) - To Charge or Not to Charge: Evidence from a Health Products Experiment in Uganda Wednesday, October 29, 2014

Abstract- In a field experiment in Uganda, we find that demand after a free distribution of three health products is lower than after a sale distribution. This contrasts with earlier work on insecticide-treated bednets, highlighting the importance of considering product characteristics in determining pricing policy. We put forward a model to illustrate the potential tension between two important factors, learning and anchoring, and then test this model with three products selected specifically for their variation in the scope for learning. We find the...

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Victor Chernozhukov (MIT) - Gaussian Approximations, Bootstrap, and Z-estimators when p >> n Wednesday, October 22, 2014

Abstract: We show that central limit theorems hold for high-dimensional normalized means hitting high-dimensional rectangles. These results apply even when p>> n. These theorems provide Gaussian distributional approximations that are not pivotal, but they can be consistently estimated via Gaussian multiplier methods and the empirical bootstrap. These results are useful for building confidence bands and for multiple testing via the step-down methods. Moreover, these results hold for approximately linear estimators. As an...

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Teppei Yamamoto (MIT) - Design, Identification, and Sensitivity Analysis for Patient Preference Trials Wednesday, October 15, 2014

Authors: Dean Knox, Teppei Yamamoto, Matthew A. Baum, and Adam Berinsky

Abstract: Social and medical scientists are often concerned that the external validity of experimental results may be compromised because of heterogeneous treatment effects. If a treatment has different effects on those who would choose to take it and those who would not, the average treatment effect estimated in a standard randomized controlled trial (RCT) may give a misleading picture of its overall impact outside of the study sample. Patient...

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Alberto Abadie (Harvard Kennedy School) - Endogenous Stratification in Randomized Experiments- Presenter: Alberto Abadi Wednesday, October 8, 2014
Abstract: Researchers and policy makers are often interested in estimating how treatments or policy interventions affect the outcomes of those most in need of help. This concern has motivated the increasingly common practice of disaggregating experimental data by groups constructed on the basis of an index of baseline characteristics that predicts the values that individual outcomes would take on in the absence of the treatment. This article shows that substantial biases may arise in practice if the index is estimated, as is often the case, by...
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Jeff Golden (Harvard Medical School) - Computational Pathology: The heart, lungs…and brain of Precision Medicine - Presenter: Jeff Golden Wednesday, October 1, 2014

Abstract: Advances in high-throughput laboratory and health information technologies are revolutionizing the disciplines of pathology and laboratory medicine.  The ability to extract clinically actionable knowledge using computational methods from complex, high-dimensional laboratory and clinical (digital) data, thereby yielding more precise diagnoses, disease stratification, and selection of patient-specific treatments, will clearly be a significant and important realization in the delivery of health care. Pathologists, who are at the nexus of...

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Georg Gerber (Harvard Medical School) - The Dynamic Microbiome Wednesday, October 1, 2014

Abstract: The microbial communities, or microbiomes, residing in the mammalian gut are inherently dynamic, changing due to many factors including host maturation, alteration of the diet, and exchange of microbes with the environment or other hosts. Recent advances in high-throughput technologies in experimental biology, such as DNA sequencing, are enabling collection of unprecedented amounts of microbiome data. I will discuss both computational and experimental projects in my lab for analyzing and generating longitudinal microbiome datasets. In...

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