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Regression Discontinuity Design
In statistics, econometrics, political science, epidemiology, and related disciplines, a regression discontinuity design (RDD) is a quasi-experimental pretest-posttest design that aims to determine the causal effects of interventions by assigning a cutoff or threshold above or below which an intervention is assigned. By comparing observations lying closely on either side of the threshold, it is possible to estimate the average treatment effect in environments in which randomisation is unfeasible. However, it remains impossible to make true causal inference with this method alone, as it does not automatically reject causal effects by any potential confounding variable. First applied by Donald Thistlethwaite and Donald Campbell (1960) to the evaluation of scholarship programs, the RDD has become increasingly popular in recent years. Recent study comparisons of randomised controlled trials (RCTs) and RDDs have empirically demonstrated the internal validity of the design. Example The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Statistics
Statistics (from German language, German: ''wikt:Statistik#German, Statistik'', "description of a State (polity), state, a country") is the discipline that concerns the collection, organization, analysis, interpretation, and presentation of data. In applying statistics to a scientific, industrial, or social problem, it is conventional to begin with a statistical population or a statistical model to be studied. Populations can be diverse groups of people or objects such as "all people living in a country" or "every atom composing a crystal". Statistics deals with every aspect of data, including the planning of data collection in terms of the design of statistical survey, surveys and experimental design, experiments.Dodge, Y. (2006) ''The Oxford Dictionary of Statistical Terms'', Oxford University Press. When census data cannot be collected, statisticians collect data by developing specific experiment designs and survey sample (statistics), samples. Representative sampling as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nonparametric Regression
Nonparametric regression is a category of regression analysis in which the predictor does not take a predetermined form but is constructed according to information derived from the data. That is, no parametric form is assumed for the relationship between predictors and dependent variable. Nonparametric regression requires larger sample sizes than regression based on parametric models because the data must supply the model structure as well as the model estimates. Definition In nonparametric regression, we have random variables X and Y and assume the following relationship: : \mathbb \mid X=x= m(x), where m(x) is some deterministic function. Linear regression is a restricted case of nonparametric regression where m(x) is assumed to be affine. Some authors use a slightly stronger assumption of additive noise: : Y = m(X) + U, where the random variable U is the `noise term', with mean 0. Without the assumption that m belongs to a specific parametric family of functions it is impo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Statistical Bias
Statistical bias is a systematic tendency which causes differences between results and facts. The bias exists in numbers of the process of data analysis, including the source of the data, the estimator chosen, and the ways the data was analyzed. Bias may have a serious impact on results, for example, to investigate people's buying habits. If the sample size is not large enough, the results may not be representative of the buying habits of all the people. That is, there may be discrepancies between the survey results and the actual results. Therefore, understanding the source of statistical bias can help to assess whether the observed results are close to the real results. Bias can be differentiated from other mistakes such as accuracy (instrument failure/inadequacy), lack of data, or mistakes in transcription (typos). Bias implies that the data selection may have been skewed by the collection criteria. Bias does not preclude the existence of any other mistakes. One may have a poo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Identifiability
In statistics, identifiability is a property which a model must satisfy for precise inference to be possible. A model is identifiable if it is theoretically possible to learn the true values of this model's underlying parameters after obtaining an infinite number of observations from it. Mathematically, this is equivalent to saying that different values of the parameters must generate different probability distributions of the observable variables. Usually the model is identifiable only under certain technical restrictions, in which case the set of these requirements is called the identification conditions. A model that fails to be identifiable is said to be non-identifiable or unidentifiable: two or more parametrizations are observationally equivalent. In some cases, even though a model is non-identifiable, it is still possible to learn the true values of a certain subset of the model parameters. In this case we say that the model is partially identifiable. In other cases it ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unbiased
Bias is a disproportionate weight ''in favor of'' or ''against'' an idea or thing, usually in a way that is closed-minded, prejudicial, or unfair. Biases can be innate or learned. People may develop biases for or against an individual, a group, or a belief. In science and engineering, a bias is a systematic error. Statistical bias results from an unfair sampling of a population, or from an estimation process that does not give accurate results on average. Etymology The word appears to derive from Old Provençal into Old French ''biais'', "sideways, askance, against the grain". Whence comes French ''biais'', "a slant, a slope, an oblique". It seems to have entered English via the game of bowls, where it referred to balls made with a greater weight on one side. Which expanded to the figurative use, "a one-sided tendency of the mind", and, at first especially in law, "undue propensity or prejudice". Types of bias Cognitive biases A cognitive bias is a repeating or basic miss ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quasi-experiment
A quasi-experiment is an empirical interventional study used to estimate the causal impact of an intervention on target population without random assignment. Quasi-experimental research shares similarities with the traditional experimental design or randomized controlled trial, but it specifically lacks the element of random assignment to treatment or control. Instead, quasi-experimental designs typically allow the researcher to control the assignment to the treatment condition, but using some criterion other than random assignment (e.g., an eligibility cutoff mark). Quasi-experiments are subject to concerns regarding internal validity, because the treatment and control groups may not be comparable at baseline. In other words, it may not be possible to convincingly demonstrate a causal link between the treatment condition and observed outcomes. This is particularly true if there are confounding variables that cannot be controlled or accounted for. With random assignment, study pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Covariate
Dependent and independent variables are variables in mathematical modeling, statistical modeling and experimental sciences. Dependent variables receive this name because, in an experiment, their values are studied under the supposition or demand that they depend, by some law or rule (e.g., by a mathematical function), on the values of other variables. Independent variables, in turn, are not seen as depending on any other variable in the scope of the experiment in question. In this sense, some common independent variables are time, space, density, mass, fluid flow rate, and previous values of some observed value of interest (e.g. human population size) to predict future values (the dependent variable). Of the two, it is always the dependent variable whose variation is being studied, by altering inputs, also known as regressors in a statistical context. In an experiment, any variable that can be attributed a value without attributing a value to any other variable is called an ind ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quarterly Journal Of Economics
''The Quarterly Journal of Economics'' is a peer-reviewed academic journal published by the Oxford University Press for the Harvard University Department of Economics. Its current editors-in-chief are Robert J. Barro, Lawrence F. Katz, Nathan Nunn, Andrei Shleifer, and Stefanie Stantcheva. History It is the oldest professional journal of economics in the English language, and covers all aspects of the field—from the journal's traditional emphasis on micro-theory to both empirical and theoretical macroeconomics. Reception According to the ''Journal Citation Reports'', the journal has a 2015 impact factor of 6.662, ranking it first out of 347 journals in the category "Economics". It is generally regarded as one of the top 5 journals in economics, together with the American Economic Review, Econometrica, the Journal of Political Economy, and the Review of Economic Studies. Notable papers Some of the most influential and well-read papers in economics have been published in th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
McCrary (2008) Density Test On Data From Lee, Moretti, And Butler (2004)
McCrary may refer to: *McCrary, Mississippi, a village in the United States *''Runyon v. McCrary ''Runyon v. McCrary'', 427 U.S. 160 (1976), was a case heard before the United States Supreme Court, which held that federal law prohibited private schools from discriminating on the basis of race.. Dissenting Justice Byron White argued that the l ...'', a Supreme Court of the United States case * McCrary (surname), people with the surname ''McCrary'' {{disambig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Journal Of Economic Literature
The ''Journal of Economic Literature'' is a peer-reviewed academic journal, published by the American Economic Association, that surveys the academic literature in economics. It was established in 1963 as the ''Journal of Economic Abstracts'',Journal of Economic Literature: About JEL retrieved 6 May 2011. and is currently one of the highest ranked journals in economics. /ref> As a , it mainly features essays and reviews of recent economic theories (as opposed to the latest research). The |
Educational Evaluation And Policy Analysis
''Educational Evaluation and Policy Analysis'' is a peer-reviewed academic journal covering all aspects of educational policy analysis. It was established in 1979 and is published by SAGE Publications on behalf of the American Educational Research Association. The editors are Joseph R. Cimpian (New York University), Julie A. Marsh (University of Southern California), Paco Martorell (University of California, Davis), and Morgan Polikoff (University of Southern California). Mission Statement ''Educational Evaluation and Policy Analysis'' (''EEPA'') publishes scholarly manuscripts of theoretical, methodological, or policy interest to those engaged in educational policy analysis, evaluation, and decision making. ''EEPA'' is a multidisciplinary policy journal, and considers original research from multiple disciplines, theoretical orientations, and methodologies. Abstracting and indexing The journal is abstracted and indexed in Scopus and the Social Sciences Citation Index. According ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Annual Review Of Political Science
''Annual Review of Political Science'' is an annual peer-reviewed academic journal published by Annual Reviews, covering significant developments in the field of political science, including political theory and philosophy, international relations, political economy, political behavior, American and comparative politics, public administration and policy, and methodology. It was established in 1998 and its editors are Margaret Levi ( Center for Advanced Study in the Behavioral Sciences, Stanford University) and Nancy Rosenblum (Harvard University). As of 2022, ''Journal Citation Reports'' gives the journal a 2021 impact factor as 12.077, ranking it first of 187 journal titles in the category "Political Science". History The ''Annual Review of Political Science'' published its first volume in 1998; the first editor was Nelson W. Polsby. Upon Polsby's death in 2007, editorship passed to Margaret Levi. She was joined by Nancy L. Rosenblum, who is credited as co-editor for issues f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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