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Identifying positively selected amino acid sites is an important approach for making inference about the function of proteins; an amino acid site that is undergoing positive selection is likely to play a key role in the function of the protein. We present a new Bayesian method for identifying positively selected amino acid sites and apply the method to a(More)
Matching methods for causal inference selectively prune observations from the data in order to reduce model dependence. They are successful when simultaneously maximizing balance (between the treated and control groups on the pre-treatment covariates) and the number of observations remaining in the data set. However, existing matching methods either fix the(More)
participants at the 2007 annual meetings of the International Studies Association, and five anonymous reviewers at the AJPS for helpful comments and advice. contributed at all stages of the project and made the primary contribution to the empirics. Michael Findley contributed at all stages of the project and made the primary contribution to the theory.(More)
We show that propensity score matching (PSM), an enormously popular method of preprocessing data for causal inference, often accomplishes the opposite of its intended goal — thus increasing imbalance, inefficiency, model dependence, and bias. PSM supposedly makes it easier to find matches by projecting a large number of covariates to a scalar propensity(More)
Recent advances in research tools for the systematic analysis of textual data are enabling exciting new research throughout the social sciences. For comparative politics scholars who are often interested in non-English and possibly multilingual textual datasets, these advances may be difficult to access. This paper discusses practical issues that arise in(More)
We highlight common problems in the application of random treatment assignment in large-scale program evaluation. Random assignment is the defining feature of modern experimental design, yet errors in design, implementation, and analysis often result in real-world applications not benefiting from its advantages. The errors discussed here cover the control(More)
We propose a simplified approach to matching for causal inference that simultaneously optimizes both balance (between the treated and control groups) and matched sample size. This procedure resolves two widespread tensions in the use of this popular methodology. First, current practice is to run a matching method that maximizes one balance metric (such as a(More)
As a result, the highest-ranking religious official in Egypt, Grand Mufti Shawki Allam, spearheaded a social media campaign urging Arabic speakers to call the group " Qa'ida Separatists in Iraq and Syria " and urging English speakers to use the acronym QSIS (and the twitter hashtag #QSIS). 2 Coverage in English-language media highlighted the Grand Mufti's(More)
DISCLAIMER This document is disseminated under the sponsorship of the Idaho Transportation Department and the United States Department of Transportation in the interest of information exchange. The State of Idaho and the United States Government assume no liability of its contents or use thereof. The contents of this report reflect the views of the(More)