David A. Freedman (statistician)
Encyclopedia
David A. Freedman was Professor of Statistics at the University of California, Berkeley
. He was a distinguished mathematical statistician whose wide-ranging research included the analysis of martingale
inequalities, Markov process
es, de Finetti's theorem
, consistency of Bayes estimator
s, sampling
, the bootstrap, and procedures for testing and evaluating models. He published extensively on methods for causal inference and the behavior of standard statistical models under non-standard conditions – for example, how regression models behave when fitted to data from randomized experiment
s. Freedman also wrote widely on the application—and misapplication—of statistics in the social sciences, including epidemiology
, public policy
, and law
.
Freedman was a consulting or testifying expert on statistics in disputes involving employment discrimination
, fair loan practices, voting rights, duplicate signatures on petitions, railroad taxation, ecological inference, flight patterns of golf ball
s, price scanner errors, Bovine Spongiform Encephalopathy
(Mad Cow disease), and sampling. He consulted for the Bank of Canada
, the Carnegie Commission, the City of San Francisco, the County of Los Angeles, and the Federal Reserve, as well as the U.S. departments of energy, treasury, justice, and commerce. Freedman and his colleague Kenneth Wachter testified to the United States Congress
and the courts against adjusting the 1980 and 1990 census
es using estimates of differential undercounts. A 1990 lawsuit that sought to compel the United States Department of Commerce
to adjust the census was heard on appeal by the U.S. Supreme Court, which ruled unanimously in favor of the Commerce Department and Freedman and Wachter's analysis. With David Kaye, Freedman wrote a widely used primer on statistics for lawyers and judges published by the Federal Judicial Center
, the education and research agency for the United States federal courts
.
In addition to his work in forensic statistics, Freedman had a broad impact on the application of statistics to important medical, social, and public policy issues, such as clinical trial
s, epidemiology
, economic models, and the interpretation of scientific experiments and observational studies. In his applied work, Freedman emphasized exposing and checking the assumptions that underlie standard methods, as well as understanding how those methods behave when the assumptions are false. He characterized circumstances in which the methods continue to perform well, and those where they break down—regardless of the quality of the data. Two of his earlier results (1963 and 1965) investigate whether or not and under what circumstances a Bayesian learning approach is consistent, i.e. when does the prior converge to the true probability distribution given sufficiently many observed data. In particular the 1965 paper with the innocent title "On the asymptotic behaviour of Bayes estimates in the discrete case II" finds the rather disappointing answer that when sampling from a countably infinite population the Bayesian procedure
fails almost everywhere, i.e. one does not obtain the true distribution asymptotically. This situation is quite different to the finite case when the (discrete) random variable takes only finite many values and the Bayesian method is consistent in aggreement with earlier findings of Doob (1948).
Freedman was the author or co-author of 200 articles, 20 technical reports and six books, including a highly innovative and influential introductory statistics textbook, Statistics (2007), with Robert Pisani and Roger Purves, which has gone through four editions. The late Amos Tversky
of Stanford University
observed that “This is a great book. It is the best introduction to how to think about statistical issues….” It has a “wealth of real-world examples that illuminate principles and applications….a classic.” Freedman’s Statistical Models: Theory and Practice (2005) is an advanced text on statistical modeling that likewise achieves a remarkable integration between extensive examples and statistical theory.
Landmark articles by Freedman include “Statistical Models and Shoe Leather” (1991), “What is the Chance of an Earthquake?” (2003), “Methods for Census 2000 and Statistical Adjustments” (2007), and “On Types of Scientific Enquiry: The Role of Qualitative Reasoning” (2008).
and the American Statistical Association
and an elected fellow of the American Academy of Arts and Sciences
. He won the 2003 John J. Carty Award for the Advancement of Science from the National Academy of Sciences
"for his profound contributions to the theory and practice of statistics, including rigorous foundations for Bayesian inference and trenchant analysis of census adjustment." He was a Fellow at the Miller Institute for Basic Research in Science in 1990, an Alfred P. Sloan Foundation
Fellow in 1964–66, and a Canada Council
Fellow at Imperial College London
in 1960–61.
Freedman was born in Montreal, Canada, on 5 March 1938. He received a B.Sc. from McGill University
in 1958 and a M.A. and a Ph.D. from Princeton University
in 1959 and 1960, respectively. He joined the University of California, Berkeley
Department of Statistics in 1961 as a lecturer and was appointed to the research faculty in 1962. He remained at Berkeley his entire career. He started his professional life as a probabilist and mathematical statistician with Bayesian leanings but became one of the world's leading applied statisticians and a circumspect frequentist.
University of California, Berkeley
The University of California, Berkeley , is a teaching and research university established in 1868 and located in Berkeley, California, USA...
. He was a distinguished mathematical statistician whose wide-ranging research included the analysis of martingale
Martingale (probability theory)
In probability theory, a martingale is a model of a fair game where no knowledge of past events can help to predict future winnings. In particular, a martingale is a sequence of random variables for which, at a particular time in the realized sequence, the expectation of the next value in the...
inequalities, Markov process
Markov process
In probability theory and statistics, a Markov process, named after the Russian mathematician Andrey Markov, is a time-varying random phenomenon for which a specific property holds...
es, de Finetti's theorem
De Finetti's theorem
In probability theory, de Finetti's theorem explains why exchangeable observations are conditionally independent given some latent variable to which an epistemic probability distribution would then be assigned...
, consistency of Bayes estimator
Bayes estimator
In estimation theory and decision theory, a Bayes estimator or a Bayes action is an estimator or decision rule that minimizes the posterior expected value of a loss function . Equivalently, it maximizes the posterior expectation of a utility function...
s, sampling
Sampling (statistics)
In statistics and survey methodology, sampling is concerned with the selection of a subset of individuals from within a population to estimate characteristics of the whole population....
, the bootstrap, and procedures for testing and evaluating models. He published extensively on methods for causal inference and the behavior of standard statistical models under non-standard conditions – for example, how regression models behave when fitted to data from randomized experiment
Randomized experiment
In science, randomized experiments are the experiments that allow the greatest reliability and validity of statistical estimates of treatment effects...
s. Freedman also wrote widely on the application—and misapplication—of statistics in the social sciences, including epidemiology
Epidemiology
Epidemiology is the study of health-event, health-characteristic, or health-determinant patterns in a population. It is the cornerstone method of public health research, and helps inform policy decisions and evidence-based medicine by identifying risk factors for disease and targets for preventive...
, public policy
Public policy
Public policy as government action is generally the principled guide to action taken by the administrative or executive branches of the state with regard to a class of issues in a manner consistent with law and institutional customs. In general, the foundation is the pertinent national and...
, and law
Law
Law is a system of rules and guidelines which are enforced through social institutions to govern behavior, wherever possible. It shapes politics, economics and society in numerous ways and serves as a social mediator of relations between people. Contract law regulates everything from buying a bus...
.
Freedman was a consulting or testifying expert on statistics in disputes involving employment discrimination
Employment discrimination
Employment discrimination is discrimination in hiring, promotion, job assignment, termination, and compensation. It includes various types of harassment....
, fair loan practices, voting rights, duplicate signatures on petitions, railroad taxation, ecological inference, flight patterns of golf ball
Golf ball
A golf ball is a ball designed to be used in the game of golf.Under the Rules of Golf, a golf ball weighs no more than 1.620 oz , has a diameter not less than 1.680 in , and performs within specified velocity, distance, and symmetry limits...
s, price scanner errors, Bovine Spongiform Encephalopathy
Bovine spongiform encephalopathy
Bovine spongiform encephalopathy , commonly known as mad-cow disease, is a fatal neurodegenerative disease in cattle that causes a spongy degeneration in the brain and spinal cord. BSE has a long incubation period, about 30 months to 8 years, usually affecting adult cattle at a peak age onset of...
(Mad Cow disease), and sampling. He consulted for the Bank of Canada
Bank of Canada
The Bank of Canada is Canada's central bank and "lender of last resort". The Bank was created by an Act of Parliament on July 3, 1934 as a privately owned corporation. In 1938, the Bank became a Crown corporation belonging to the Government of Canada...
, the Carnegie Commission, the City of San Francisco, the County of Los Angeles, and the Federal Reserve, as well as the U.S. departments of energy, treasury, justice, and commerce. Freedman and his colleague Kenneth Wachter testified to the United States Congress
United States Congress
The United States Congress is the bicameral legislature of the federal government of the United States, consisting of the Senate and the House of Representatives. The Congress meets in the United States Capitol in Washington, D.C....
and the courts against adjusting the 1980 and 1990 census
Census
A census is the procedure of systematically acquiring and recording information about the members of a given population. It is a regularly occurring and official count of a particular population. The term is used mostly in connection with national population and housing censuses; other common...
es using estimates of differential undercounts. A 1990 lawsuit that sought to compel the United States Department of Commerce
United States Department of Commerce
The United States Department of Commerce is the Cabinet department of the United States government concerned with promoting economic growth. It was originally created as the United States Department of Commerce and Labor on February 14, 1903...
to adjust the census was heard on appeal by the U.S. Supreme Court, which ruled unanimously in favor of the Commerce Department and Freedman and Wachter's analysis. With David Kaye, Freedman wrote a widely used primer on statistics for lawyers and judges published by the Federal Judicial Center
Federal Judicial Center
The Federal Judicial Center is the education and research agency of the United States federal courts. It was established by an Act of Congress in 1967, at the recommendation of the Judicial Conference of the United States....
, the education and research agency for the United States federal courts
United States federal courts
The United States federal courts make up the judiciary branch of federal government of the United States organized under the United States Constitution and laws of the federal government.-Categories:...
.
In addition to his work in forensic statistics, Freedman had a broad impact on the application of statistics to important medical, social, and public policy issues, such as clinical trial
Clinical trial
Clinical trials are a set of procedures in medical research and drug development that are conducted to allow safety and efficacy data to be collected for health interventions...
s, epidemiology
Epidemiology
Epidemiology is the study of health-event, health-characteristic, or health-determinant patterns in a population. It is the cornerstone method of public health research, and helps inform policy decisions and evidence-based medicine by identifying risk factors for disease and targets for preventive...
, economic models, and the interpretation of scientific experiments and observational studies. In his applied work, Freedman emphasized exposing and checking the assumptions that underlie standard methods, as well as understanding how those methods behave when the assumptions are false. He characterized circumstances in which the methods continue to perform well, and those where they break down—regardless of the quality of the data. Two of his earlier results (1963 and 1965) investigate whether or not and under what circumstances a Bayesian learning approach is consistent, i.e. when does the prior converge to the true probability distribution given sufficiently many observed data. In particular the 1965 paper with the innocent title "On the asymptotic behaviour of Bayes estimates in the discrete case II" finds the rather disappointing answer that when sampling from a countably infinite population the Bayesian procedure
Bayesian inference
In statistics, Bayesian inference is a method of statistical inference. It is often used in science and engineering to determine model parameters, make predictions about unknown variables, and to perform model selection...
fails almost everywhere, i.e. one does not obtain the true distribution asymptotically. This situation is quite different to the finite case when the (discrete) random variable takes only finite many values and the Bayesian method is consistent in aggreement with earlier findings of Doob (1948).
Freedman was the author or co-author of 200 articles, 20 technical reports and six books, including a highly innovative and influential introductory statistics textbook, Statistics (2007), with Robert Pisani and Roger Purves, which has gone through four editions. The late Amos Tversky
Amos Tversky
Amos Nathan Tversky, was a cognitive and mathematical psychologist, a pioneer of cognitive science, a longtime collaborator of Daniel Kahneman, and a key figure in the discovery of systematic human cognitive bias and handling of risk. Much of his early work concerned the foundations of measurement...
of Stanford University
Stanford University
The Leland Stanford Junior University, commonly referred to as Stanford University or Stanford, is a private research university on an campus located near Palo Alto, California. It is situated in the northwestern Santa Clara Valley on the San Francisco Peninsula, approximately northwest of San...
observed that “This is a great book. It is the best introduction to how to think about statistical issues….” It has a “wealth of real-world examples that illuminate principles and applications….a classic.” Freedman’s Statistical Models: Theory and Practice (2005) is an advanced text on statistical modeling that likewise achieves a remarkable integration between extensive examples and statistical theory.
Landmark articles by Freedman include “Statistical Models and Shoe Leather” (1991), “What is the Chance of an Earthquake?” (2003), “Methods for Census 2000 and Statistical Adjustments” (2007), and “On Types of Scientific Enquiry: The Role of Qualitative Reasoning” (2008).
Biography and awards
Freedman was a fellow of the Institute of Mathematical StatisticsInstitute of Mathematical Statistics
The Institute of Mathematical Statistics is an international professional and scholarly society devoted to the development, dissemination, and application of statistics and probability. The Institute currently has about 4,000 members in all parts of the world...
and the American Statistical Association
American Statistical Association
The American Statistical Association , is the main professional US organization for statisticians and related professions. It was founded in Boston, Massachusetts on November 27, 1839, and is the second oldest, continuously operating professional society in the United States...
and an elected fellow of the American Academy of Arts and Sciences
American Academy of Arts and Sciences
The American Academy of Arts and Sciences is an independent policy research center that conducts multidisciplinary studies of complex and emerging problems. The Academy’s elected members are leaders in the academic disciplines, the arts, business, and public affairs.James Bowdoin, John Adams, and...
. He won the 2003 John J. Carty Award for the Advancement of Science from the National Academy of Sciences
United States National Academy of Sciences
The National Academy of Sciences is a corporation in the United States whose members serve pro bono as "advisers to the nation on science, engineering, and medicine." As a national academy, new members of the organization are elected annually by current members, based on their distinguished and...
"for his profound contributions to the theory and practice of statistics, including rigorous foundations for Bayesian inference and trenchant analysis of census adjustment." He was a Fellow at the Miller Institute for Basic Research in Science in 1990, an Alfred P. Sloan Foundation
Alfred P. Sloan Foundation
The Alfred P. Sloan Foundation is a philanthropic non-profit organization in the United States. It was established in 1934 by Alfred P. Sloan, Jr., then-President and Chief Executive Officer of General Motors.-Overview:...
Fellow in 1964–66, and a Canada Council
Canada Council
The Canada Council for the Arts, commonly called the Canada Council, is a Crown Corporation established in 1957 to act as an arts council of the government of Canada, created to foster and promote the study and enjoyment of, and the production of works in, the arts. It funds Canadian artists and...
Fellow at Imperial College London
Imperial College London
Imperial College London is a public research university located in London, United Kingdom, specialising in science, engineering, business and medicine...
in 1960–61.
Freedman was born in Montreal, Canada, on 5 March 1938. He received a B.Sc. from McGill University
McGill University
Mohammed Fathy is a public research university located in Montreal, Quebec, Canada. The university bears the name of James McGill, a prominent Montreal merchant from Glasgow, Scotland, whose bequest formed the beginning of the university...
in 1958 and a M.A. and a Ph.D. from Princeton University
Princeton University
Princeton University is a private research university located in Princeton, New Jersey, United States. The school is one of the eight universities of the Ivy League, and is one of the nine Colonial Colleges founded before the American Revolution....
in 1959 and 1960, respectively. He joined the University of California, Berkeley
University of California, Berkeley
The University of California, Berkeley , is a teaching and research university established in 1868 and located in Berkeley, California, USA...
Department of Statistics in 1961 as a lecturer and was appointed to the research faculty in 1962. He remained at Berkeley his entire career. He started his professional life as a probabilist and mathematical statistician with Bayesian leanings but became one of the world's leading applied statisticians and a circumspect frequentist.