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Instrumental Variable
In statistics, econometrics, epidemiology and related disciplines, the method of instrumental variables (IV) is used to estimate causal relationships when controlled experiments are not feasible or when a treatment is not successfully delivered to every unit in a randomized experiment. Intuitively, IVs are used when an explanatory variable of interest is correlated with the error term, in which case ordinary least squares and ANOVA give biased results. A valid instrument induces changes in the explanatory variable but has no independent effect on the dependent variable, allowing a researcher to uncover the causal effect of the explanatory variable on the dependent variable. Instrumental variable methods allow for consistent estimation when the explanatory variables (covariates) are correlated with the error terms in a regression model. Such correlation may occur when: # changes in the dependent variable change the value of at least one of the covariates ("reverse" causation), # ... [...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] |
Endogeneity (econometrics)
In econometrics, endogeneity broadly refers to situations in which an explanatory variable is correlated with the error term. The distinction between endogenous and exogenous variables originated in simultaneous equations models, where one separates variables whose values are determined by the model from variables which are predetermined; ignoring simultaneity in the estimation leads to biased estimates as it violates the exogeneity assumption of the Gauss–Markov theorem. The problem of endogeneity is often ignored by researchers conducting non-experimental research and doing so precludes making policy recommendations. Instrumental variable techniques are commonly used to address this problem. Besides simultaneity, correlation between explanatory variables and the error term can arise when an unobserved or omitted variable is confounding both independent and dependent variables, or when independent variables are measured with error. Exogeneity versus endogeneity In a sto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alan Krueger
Alan Bennett Krueger (September 17, 1960 – March 16, 2019) was an American economist who was the James Madison Professor of Political Economy at Princeton University and Research Associate at the National Bureau of Economic Research. He served as Assistant Secretary of the Treasury for Economic Policy, nominated by President Barack Obama, from May 2009 to October 2010, when he returned to Princeton. He was nominated in 2011 by Obama as chair of the White House Council of Economic Advisers, and served in that office from November 2011 to August 2013. He was among the 50 highest ranked economists in the world according to Research Papers in Economics. Early life and education Krueger grew up in a Jewish family in Livingston, New Jersey, and graduated from Livingston High School in 1979. Krueger received his B.S. from the Cornell University School of Industrial and Labor Relations (with honors), and he received his A.M. and Ph.D. in Economics from Harvard University in 1985 a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Joshua Angrist
Joshua David Angrist (born September 18, 1960) is an Israeli-American economist and Ford Professor of Economics at the Massachusetts Institute of Technology. Angrist, together with Guido Imbens, was awarded the Nobel Memorial Prize in Economics in 2021 "for their methodological contributions to the analysis of causal relationships". He ranks among the world's top economists in labor economics, urban economics, and the economics of education, and is known for his use of quasi-experimental research designs (such as instrumental variables) to study the effects of public policies and changes in economic or social circumstances. He is a co-founder and co-director of the MIT'School Effectiveness & Inequality Initiative which studies the relationship between human capital and income inequality in the U.S. Biography Angrist was born to a Jewish family in Columbus, Ohio, and raised in Pittsburgh, Pennsylvania, where he graduated from Taylor Allderdice High School in 1977. Angrist re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Journal Of Clinical Epidemiology
The ''Journal of Clinical Epidemiology'' is a peer-reviewed journal of epidemiology. The journal was originally established as the ''Journal of Chronic Diseases'' in 1955 as a follow-up to Harry S. Truman's 1951 Presidential Task Force on national health concerns and the subsequently written Magnuson Report. Under the editorial leadership of Alvan Feinstein and Walter O. Spitzer, the title of the journal was changed to the ''Journal of Clinical Epidemiology'' with the January 1988 issue. The current editors are André Knottnerus (Netherlands School of Primary Care Research) and Peter Tugwell (University of Ottawa). According to the ''Journal Citation Reports'', the journal has a 2020 Impact Factor The impact factor (IF) or journal impact factor (JIF) of an academic journal is a scientometric index calculated by Clarivate that reflects the yearly mean number of citations of articles published in the last two years in a given journal, as i ... of 6.437, ranking it 5th out of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Estimation
Estimation (or estimating) is the process of finding an estimate or approximation, which is a value that is usable for some purpose even if input data may be incomplete, uncertain, or unstable. The value is nonetheless usable because it is derived from the best information available.C. Lon Enloe, Elizabeth Garnett, Jonathan Miles, ''Physical Science: What the Technology Professional Needs to Know'' (2000), p. 47. Typically, estimation involves "using the value of a statistic derived from a sample to estimate the value of a corresponding population parameter".Raymond A. Kent, "Estimation", ''Data Construction and Data Analysis for Survey Research'' (2001), p. 157. The sample provides information that can be projected, through various formal or informal processes, to determine a range most likely to describe the missing information. An estimate that turns out to be incorrect will be an overestimate if the estimate exceeds the actual result and an underestimate if the estimate fall ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frisch–Waugh–Lovell Theorem
In econometrics, the Frisch–Waugh–Lovell (FWL) theorem is named after the econometricians Ragnar Frisch, Frederick V. Waugh, and Michael C. Lovell. The Frisch–Waugh–Lovell theorem states that if the regression we are concerned with is: : Y = X_1 \beta_1 + X_2 \beta_2 + u where X_1 and X_2 are n \times k_1 and n \times k_2 matrices respectively and where \beta_1 and \beta_2 are conformable, then the estimate of \beta_2 will be the same as the estimate of it from a modified regression of the form: : M_ Y = M_ X_2 \beta_2 + M_ u, where M_ projects onto the orthogonal complement of the image of the projection matrix X_1(X_1^X_1)^X_1^ . Equivalently, ''M''''X''1 projects onto the orthogonal complement of the column space of ''X''1. Specifically, : M_ = I - X_1(X_1^X_1)^X_1^, and this particular orthogonal projection matrix is known as the residual maker matrix or annihilator matrix. The vector M_ Y is the vector of residuals from regression of Y on th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Errors-in-variables Models
In statistics, errors-in-variables models or measurement error models are regression models that account for measurement errors in the independent variables. In contrast, standard regression models assume that those regressors have been measured exactly, or observed without error; as such, those models account only for errors in the dependent variables, or responses. In the case when some regressors have been measured with errors, estimation based on the standard assumption leads to inconsistent estimates, meaning that the parameter estimates do not tend to the true values even in very large samples. For simple linear regression the effect is an underestimate of the coefficient, known as the '' attenuation bias''. In non-linear models the direction of the bias is likely to be more complicated. Motivating example Consider a simple linear regression model of the form : y_ = \alpha + \beta x_^ + \varepsilon_t\,, \quad t=1,\ldots,T, where x_^ denotes the ''true'' but unob ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Olav Reiersøl
Olav Reiersøl (28 June 1908 – 14 February 2001) was a Norwegian statistician and econometrician, who made several substantial contributions to econometrics and statistics. His works on identifiability and instrumental variables are standard references both in econometrics and statistics, and his work on genetic algebras are frequently cited in genetics. Reiersøl became interested in the international language Esperanto at a young age, and later in life used it to keep in touch with other mathematicians. He was one of the founders of the Esperanto association ''Internacia Asocio de Esperantistaj Matematikistoj'' ("International Association of Esperantist Mathematicians"). ''Econometric Theory'', 16, 2000, 113-125. He was made a fellow of the |
Journal Of Economic Perspectives
The ''Journal of Economic Perspectives'' (JEP) is an economic journal published by the American Economic Association. The journal was established in 1987. It is very broad in its scope. According to its editors its purpose is: #to synthesize and integrate lessons learned from active lines of economic research; #to provide economic analysis of public policy issues; to encourage cross-fertilization of ideas among the fields of thinking; #to offer readers an accessible source for state-of-the-art economic thinking; #to suggest directions for future research; #to provide insights and readings for classroom use; #and to address issues relating to the economics profession.'' Its current editor is Heidi Williams, and its managing editor A managing editor (ME) is a senior member of a publication's management team. Typically, the managing editor reports directly to the editor-in-chief and oversees all aspects of the publication. United States In the United States, a managing edit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Statistical Review
The International Statistical Institute (ISI) is a professional association of statisticians. It was founded in 1885, although there had been international statistical congresses since 1853. The institute has about 4,000 elected members from government, academia, and the private sector. The affiliated Associations have membership open to any professional statistician. The institute publishes a variety of books and journals, and holds an international conference every two years. The biennial convention was commonly known as the ISI Session; however, since 2011, it is now referred to as the ISI World Statistics Congress. The permanent office of the institute is located in the Statistics Netherlands building in Leidschenveen (The Hague), in the Netherlands. Specialized Associations ISI serves as an umbrella for seven specialized Associations: * Bernoulli Society for Mathematical Statistics and Probability (BS) *International Association for Statistical Computing (IASC) *Internatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
James Heckman
James Joseph Heckman (born April 19, 1944) is a Nobel Prize-winning American economist at the University of Chicago, where he is The Henry Schultz Distinguished Service Professor in Economics and the College; Professor at the Harris School of Public Policy; Director of the Center for the Economics of Human Development (CEHD); and Co-Director of Human Capital and Economic Opportunity (HCEO) Global Working Group. He is also Professor of Law at the Law School, a senior research fellow at the American Bar Foundation, and a research associate at the National Bureau of Economic Research. In 2000, Heckman shared the Nobel Memorial Prize in Economic Sciences with Daniel McFadden, for his pioneering work in econometrics and microeconomics. As of December 2020, according to RePEc, he is the second-most influential economist in the world. Early years Heckman was born to John Jacob Heckman and Bernice Irene Medley in Chicago, Illinois. He received his B.A. in mathematics from Colorado Coll ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
