Glenn Firebaugh
Encyclopedia
Glenn Firebaugh is an American sociologist (born: Charleston, West Virginia
) and leading international authority on social science research methods. Currently he is Distinguished Professor of Sociology at the Pennsylvania State University
. He has also held regular or visiting faculty appointments at Harvard University
, Vanderbilt University
, and the University of Michigan
.
Firebaugh is best known for his contributions to statistical methods and for his research on global inequality. His publications are highly cited by other social scientists.
; others include the Atkinson measure, the Theil index
, the Robin Hood index
, and many others.
Firebaugh has shown that standard inequality indices reduce to a convenient common form. He begins by noting that perfect equality exists when the inequality ratio, rj = Xj /
equals 1.0 for all j units in some population (for example, there is perfect income inequality when everyone’s income Xj equals the mean income 
, so that rj = 1.0 for everyone). Inequality, then, refers to deviations of the rj from 1.0; the greater the average deviation, the greater the inequality. Inequality indices reflect that fact because they have this common form:
where pj weights the units by their population share (necessary in a cross-country analysis, for example, since countries vary in population), and f(rj) is a function of the deviation of each unit’s rj from 1.0, the point of equality. The important insight of Firebaugh’s general inequality equation is that inequality indices differ because they employ different functions of the distance of the inequality ratios (the rj) from 1.0.
, a four-term governor of Alabama
and well-known segregationist who ran as a third-party candidate well in the 1968 US Presidential election, received a higher share of votes in regions with higher percentages of blacks. From this one might erroneously conclude that blacks were disproportionately inclined to vote for Wallace (post-election surveys showed that, while one in eight whites voted for Wallace, virtually no blacks did).
Firebaugh has contributed to this literature by delineating theoretical conditions or rules under which it is possible to infer individual-level relationships from aggregate data. These conditions are important because researchers are subject to the ecological fallacy in virtually all the social and behavioral sciences - from history to political science to epidemiology – since individual-level data often are unavailable.
Charleston, West Virginia
Charleston is the capital and largest city of the U.S. state of West Virginia. It is located at the confluence of the Elk and Kanawha Rivers in Kanawha County. As of the 2010 census, it has a population of 51,400, and its metropolitan area 304,214. It is the county seat of Kanawha County.Early...
) and leading international authority on social science research methods. Currently he is Distinguished Professor of Sociology at the Pennsylvania State University
Pennsylvania State University
The Pennsylvania State University, commonly referred to as Penn State or PSU, is a public research university with campuses and facilities throughout the state of Pennsylvania, United States. Founded in 1855, the university has a threefold mission of teaching, research, and public service...
. He has also held regular or visiting faculty appointments at Harvard University
Harvard University
Harvard University is a private Ivy League university located in Cambridge, Massachusetts, United States, established in 1636 by the Massachusetts legislature. Harvard is the oldest institution of higher learning in the United States and the first corporation chartered in the country...
, Vanderbilt University
Vanderbilt University
Vanderbilt University is a private research university located in Nashville, Tennessee, United States. Founded in 1873, the university is named for shipping and rail magnate "Commodore" Cornelius Vanderbilt, who provided Vanderbilt its initial $1 million endowment despite having never been to the...
, and the University of Michigan
University of Michigan
The University of Michigan is a public research university located in Ann Arbor, Michigan in the United States. It is the state's oldest university and the flagship campus of the University of Michigan...
.
Firebaugh is best known for his contributions to statistical methods and for his research on global inequality. His publications are highly cited by other social scientists.
Rules for Social Research
Firebaugh summarizes the principles for good research in his book Seven Rules for Social Research. The first rule is that “There should be the possibility of surprise in social research.” Good research also will “look for differences that make a difference” (Rule 2) and “build in reality checks” (Rule 3). Rule 4 advises researchers to replicate, that is, “to see if identical analyses yield similar results for different samples of people” (p. 90). The next two rules urge researchers to “compare like with like” (Rule 5) and to “study change” (Rule 6); these two rules are especially important when researchers want to estimate the effect of one variable on another. The final rule, “Let method be the servant, not the master,” reminds researchers that methods are the means, not the end, of social research; it is critical from the outset to fit the research design to the research issue, rather than the other way around.Firebaugh’s general equation for inequality indices
Inequality indices are scalar measures designed to quantify the degree of inequality in distributions of some valued good, such as income. Researchers often use inequality indices to compare the degree of inequality across populations (for example, to determine if there is greater income inequality in California than in Texas, or in Brazil versus South Africa). The best-known inequality index is the Gini coefficientGini coefficient
The Gini coefficient is a measure of statistical dispersion developed by the Italian statistician and sociologist Corrado Gini and published in his 1912 paper "Variability and Mutability" ....
; others include the Atkinson measure, the Theil index
Theil index
The Theil index is a statistic used to measure economic inequality. It has also been used to measure the lack of racial diversity. The basic Theil index TT is the same as redundancy in information theory which is the maximum possible entropy of the data minus the observed entropy. It is a special...
, the Robin Hood index
Robin Hood index
The Hoover index is a measure of income inequality. It is equal to the portion of the total community income that would have to be redistributed for there to be perfect equality....
, and many others.
Firebaugh has shown that standard inequality indices reduce to a convenient common form. He begins by noting that perfect equality exists when the inequality ratio, rj = Xj /
equals 1.0 for all j units in some population (for example, there is perfect income inequality when everyone’s income Xj equals the mean income , so that rj = 1.0 for everyone). Inequality, then, refers to deviations of the rj from 1.0; the greater the average deviation, the greater the inequality. Inequality indices reflect that fact because they have this common form:-
- Inequality Index =
- Inequality Index =
where pj weights the units by their population share (necessary in a cross-country analysis, for example, since countries vary in population), and f(rj) is a function of the deviation of each unit’s rj from 1.0, the point of equality. The important insight of Firebaugh’s general inequality equation is that inequality indices differ because they employ different functions of the distance of the inequality ratios (the rj) from 1.0.
Trends in global income inequality
Firebaugh was among the first to note that income inequality for the world as a whole leveled off in the last decades of the 20th century, after rising for more than two centuries. Firebaugh describes this important turning point in a 1999 lead article in the American Journal of Sociology and in a 2003 book. While global income inequality is massive, it has remained relatively steady or declined somewhat in recent years due to rapid income growth in China and India. Firebaugh’s findings challenged earlier claims that global income inequality continues to rise rapidly. According to Firebaugh, that claim was based on a flaw: Each country was assigned equal weighting, despite vast differences in population size. When populous countries such as China and India are given their due weight, the data show that global income inequality has not been rising sharply, and most likely is not rising at all. Firebaugh’s findings have been verified by others. As a result, earlier claims by the United Nations and the World Bank of rapidly-rising global income inequality have been modified in their more recent publications.Avoiding the ecological fallacy
Researchers are said to commit the ecological fallacy when they make untested inferences about individual-level relationships from aggregate data. It is called a fallacy because it is based on the problematic assumption that relationships at one level of aggregation also hold at another level of aggregation. To illustrate, consider the fact that George WallaceGeorge Wallace
George Corley Wallace, Jr. was the 45th Governor of Alabama, serving four terms: 1963–1967, 1971–1979 and 1983–1987. "The most influential loser" in 20th-century U.S. politics, according to biographers Dan T. Carter and Stephan Lesher, he ran for U.S...
, a four-term governor of Alabama
Alabama
Alabama is a state located in the southeastern region of the United States. It is bordered by Tennessee to the north, Georgia to the east, Florida and the Gulf of Mexico to the south, and Mississippi to the west. Alabama ranks 30th in total land area and ranks second in the size of its inland...
and well-known segregationist who ran as a third-party candidate well in the 1968 US Presidential election, received a higher share of votes in regions with higher percentages of blacks. From this one might erroneously conclude that blacks were disproportionately inclined to vote for Wallace (post-election surveys showed that, while one in eight whites voted for Wallace, virtually no blacks did).
Firebaugh has contributed to this literature by delineating theoretical conditions or rules under which it is possible to infer individual-level relationships from aggregate data. These conditions are important because researchers are subject to the ecological fallacy in virtually all the social and behavioral sciences - from history to political science to epidemiology – since individual-level data often are unavailable.
Prizes and Awards
- Taiwan National Science Council Distinguished Lecturer, Academia Sinica,Taipei, 2005
- Faculty Scholar Medal for Outstanding Achievement in the Social and Behavioral Sciences, Pennsylvania State University, 2001
- Best-Article Prize, Center for the Study of Inequality, Cornell University, 2001, for “Empirics of World Income Inequality” (American Journal of Sociology, May 1999)
- Lecturer, Zentrum fur Umbragen, Methoden und Analysen, Mannheim, Germany, 2000
- Distinction in the Social Sciences Award, College of the Liberal Arts, Pennsylvania State University, 2000
- Member, Sociological Research Association
- NIMH Fellow in Quantitative Methods, Indiana UniversityIndiana UniversityIndiana University is a multi-campus public university system in the state of Indiana, United States. Indiana University has a combined student body of more than 100,000 students, including approximately 42,000 students enrolled at the Indiana University Bloomington campus and approximately 37,000...
, Bloomington, IN