Lee Cronbach
Encyclopedia
Lee Joseph Cronbach was an American
educational psychologist
who made significant contributions to psychological testing and measurement. Born in Fresno
, California
, Cronbach was selected as a child to participate in Lewis Terman's long-term study of talented children
. He received a bachelor's degree from Fresno State College and a master's degree from the University of California, Berkeley
. Cronbach had an interest in educational and psychological measurement due to Thurstone’s work on the measurement of attitudes. This work of Thurstone intruiged Cronbach; motivating him to complete and receive his doctorate
in educational psychology
from the University of Chicago
in 1940. In 1948, at the University of Illinois, Urbana, Cronbach produced many of his most influential work: the "Alpha" paper (Cronbach, 1951), as well as a notable essay titled The Two Disciplines of Scientific Psychology, in the American Psychologist
magazine in 1957, where he discussed his thoughts on the increasing divergence between the fields of experimental psychology
and correlational psychology (to which he himself belonged). After teaching mathematics and chemistry at Fresno High School, Cronbach took faculty positions at the State College of Washington, the University of Chicago, and the University of Illinois
, finally settling at Stanford University
in 1964. Cronbach was the president of the American Psychological Association
, president of the American Educational Research Association
, Vida Jacks Professor of Education at Stanford University and a member of the United States National Academy of Sciences
. Cronbach is considered to be "one of the most prominent and influential educational psychologists of all time."
Educational psychologists have benefited from Cronbach's quest for a better explanation of learning in response to instruction; making countless contributions to educational psychology. Cronbach was able to sharpen the sensitivity of educational research - just as how different learners cope with the demands within different learning environments. He advocated the use of extensive local studies and field methods, producing useful narratives of teaching and learning. Refining research questions which seek to understand the person-situation interactions in educational settings, recognizing the abandonment of strict scientism is in favour of a more pluralistic philosophical and empirical agenda, and emphasizing that the role of context is just as essential as improved interpretations of educational processes is just a brief overview of Cronbach's contributions. Cronbach developed a framework for evaluation design, implementation and analysis. He believed that the purpose of evaluation to provide constructive feedback for program implementers and clients was incorrect. On the contrary, he believed that it was the design, implementation and analysis which should reflect the feedback goal.
Cronbach has proven that research is indeed, valuable - to the extent where research serves the purpose of improving some aspect of social reality. This allowed Cronbach to lay out guidelines - much like a road-map - for researchers and practitioners of educational psychology spreading awareness of the challenges and prospects of conducting program evaluations.
"The special task of the social scientist in each generation is to pin down the contemporary facts. Beyond that, [Cronbach] shares with the humanistic scholar and the artist in the effort to gain insight into contemporary relationships, and to align the culture’s view of man with present realities. To know man as he is is no mean aspiration."
, a method for determining the reliability of educational and psychological tests. This allowed new interpretations to the index of reliability. Cronbach had created this formula which could be applied throughout a variety of tests and other measurement instruments - gaining an enormous amount of popularity among practitioners.
Cronbach's Alpha provided a measure of reliability from a single test administration thus showing that on repeated occasions, or even other parallel forms of testing, were not needed to estimate a test's consistency (this followed closely from the works of Kuder and Richardson). The Alpha is useful because not only is it easily calculated, but it is also quite general and can be applied universally - for example: dichotomously scored multiple-choice items or polytimous attitude scales.
. He began his work with the aim to produce a handbook on measurement - allowing people to apply mathematical concepts to transform one’s behaviours and events into quantitative results. Cronbach believed that there were two flaws in the concept of taking observed test scores into true score and error components: he believed that true scores were "ill-defined" and errors were "all-inclusive". The Generalizability theory addresses the question of the relative influence on test performance based on different aspects of how tests are being administered to people. A question that would be addressed, for example, would be: "will students perform consistently on different occasions?"
The Generalizability theory expanded when Cronbach became concerned that an undifferentiated error term covered up information about systematic variations which could be important in terms of test performance. With this in mind, he teamed up with two other members and developed a "random model" (introduced by a statistician R.A. Fisher) where he was determined to figure out the complexities of error variance. This "G" theory thus provided a combination of the psychological with the mathematical producing a comprehensive framework and statistical model which identified sources of measurement error.
Cronbach's theory goes beyond simply examining consistency in a student’s relative standing in distribution – it recognizes and acknowledges that the particular item used in any given test is only a small indicator from a wider domain of knowledge. Only such extensions to reliability investigations were made possible by the Generalizability theory - which allowed researchers to address more realistic educational problems, and encouraged researchers to place substantial considerations when they made inquires to demonstrate that validity is important especially when evaluating information extracted from test scores.
However, Cronbach's work on validity was no less important nor influential - with the help from Paul Meehl, he placed the concept of validity theory in the centre of educational and psychological testing. Cronbach & Meehl believed that "...it [is]imperative that psychologists make a place for [advocating construct validity] in their methodological thinking, so that its rationale, its scientific legitimacy, and its dangers may become explicit and familiar. This would be preferable to the widespread current tendency to engage in what actually amounts to construct validation research and use of constructs in practical testing, while talking an "operational" methodology which, if adopted, would force research into a mold it does not fit." Cronbach acknowledged reliability as an important characteristic of a test, but believed that reliability and validity went hand-in-hand,and at times, 'trade-offs' were necessary in order to improve reliability. The paper, Construct Validity in Psychological Tests, compiled by both Cronbach and Meehl, represents their research efforts for over 50 years on validity.
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
educational psychologist
Educational psychology
Educational psychology is the study of how humans learn in educational settings, the effectiveness of educational interventions, the psychology of teaching, and the social psychology of schools as organizations. Educational psychology is concerned with how students learn and develop, often focusing...
who made significant contributions to psychological testing and measurement. Born in Fresno
Fresno, California
Fresno is a city in central California, United States, the county seat of Fresno County. As of the 2010 census, the city's population was 510,365, making it the fifth largest city in California, the largest inland city in California, and the 34th largest in the nation...
, California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
, Cronbach was selected as a child to participate in Lewis Terman's long-term study of talented children
Genetic Studies of Genius
The Genetic Studies of Genius, today known as the Terman Study of the Gifted, is a still-running longitudinal study begun in 1921 to examine the development and characteristics of gifted children into adulthood...
. He received a bachelor's degree from Fresno State College and a master's degree from 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...
. Cronbach had an interest in educational and psychological measurement due to Thurstone’s work on the measurement of attitudes. This work of Thurstone intruiged Cronbach; motivating him to complete and receive his doctorate
Doctorate
A doctorate is an academic degree or professional degree that in most countries refers to a class of degrees which qualify the holder to teach in a specific field, A doctorate is an academic degree or professional degree that in most countries refers to a class of degrees which qualify the holder...
in educational psychology
Educational psychology
Educational psychology is the study of how humans learn in educational settings, the effectiveness of educational interventions, the psychology of teaching, and the social psychology of schools as organizations. Educational psychology is concerned with how students learn and develop, often focusing...
from the University of Chicago
University of Chicago
The University of Chicago is a private research university in Chicago, Illinois, USA. It was founded by the American Baptist Education Society with a donation from oil magnate and philanthropist John D. Rockefeller and incorporated in 1890...
in 1940. In 1948, at the University of Illinois, Urbana, Cronbach produced many of his most influential work: the "Alpha" paper (Cronbach, 1951), as well as a notable essay titled The Two Disciplines of Scientific Psychology, in the American Psychologist
American Psychologist
The American Psychologist is the official academic journal of the American Psychological Association. It contains archival documents and articles covering current issues in psychology, the science and practice of psychology, and psychology's contribution to public policy...
magazine in 1957, where he discussed his thoughts on the increasing divergence between the fields of experimental psychology
Experimental psychology
Experimental psychology is a methodological approach, rather than a subject, and encompasses varied fields within psychology. Experimental psychologists have traditionally conducted research, published articles, and taught classes on neuroscience, developmental psychology, sensation, perception,...
and correlational psychology (to which he himself belonged). After teaching mathematics and chemistry at Fresno High School, Cronbach took faculty positions at the State College of Washington, the University of Chicago, and the University of Illinois
University of Illinois at Urbana-Champaign
The University of Illinois at Urbana–Champaign is a large public research-intensive university in the state of Illinois, United States. It is the flagship campus of the University of Illinois system...
, finally settling at 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...
in 1964. Cronbach was the president of the American Psychological Association
American Psychological Association
The American Psychological Association is the largest scientific and professional organization of psychologists in the United States. It is the world's largest association of psychologists with around 154,000 members including scientists, educators, clinicians, consultants and students. The APA...
, president of the American Educational Research Association
American Educational Research Association
The American Educational Research Association, or AERA, was founded in 1916 as a professional organization representing educational researchers in the United States and around the world....
, Vida Jacks Professor of Education at Stanford University and a member of the United States 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...
. Cronbach is considered to be "one of the most prominent and influential educational psychologists of all time."
Contributions to educational psychology
Cronbach's research can be clustered into three main areas: measurement theory, program evaluation, and instruction. This includes several issues, such as the nature of the teaching-learning process, the measurement of variables describing instructional interactions, the evaluation of educational programs, and educational psychology’s aspiration as an emerging social science discipline. His contributions to measurement issues were of great importance to all educational psychologists. These contributions included improvements to the technology of psychometric modeling, as well as reformulations, which went beyond the mathematics of understanding the psychology of test performances.Educational psychologists have benefited from Cronbach's quest for a better explanation of learning in response to instruction; making countless contributions to educational psychology. Cronbach was able to sharpen the sensitivity of educational research - just as how different learners cope with the demands within different learning environments. He advocated the use of extensive local studies and field methods, producing useful narratives of teaching and learning. Refining research questions which seek to understand the person-situation interactions in educational settings, recognizing the abandonment of strict scientism is in favour of a more pluralistic philosophical and empirical agenda, and emphasizing that the role of context is just as essential as improved interpretations of educational processes is just a brief overview of Cronbach's contributions. Cronbach developed a framework for evaluation design, implementation and analysis. He believed that the purpose of evaluation to provide constructive feedback for program implementers and clients was incorrect. On the contrary, he believed that it was the design, implementation and analysis which should reflect the feedback goal.
Cronbach has proven that research is indeed, valuable - to the extent where research serves the purpose of improving some aspect of social reality. This allowed Cronbach to lay out guidelines - much like a road-map - for researchers and practitioners of educational psychology spreading awareness of the challenges and prospects of conducting program evaluations.
"The special task of the social scientist in each generation is to pin down the contemporary facts. Beyond that, [Cronbach] shares with the humanistic scholar and the artist in the effort to gain insight into contemporary relationships, and to align the culture’s view of man with present realities. To know man as he is is no mean aspiration."
Cronbach's alpha
Cronbach worked on the concept of reliability which had a huge impact on the field of educational measurement. His earliest work was the development of Cronbach's alphaCronbach's alpha
Cronbach's \alpha is a coefficient of reliability. It is commonly used as a measure of the internal consistency or reliability of a psychometric test score for a sample of examinees. It was first named alpha by Lee Cronbach in 1951, as he had intended to continue with further coefficients...
, a method for determining the reliability of educational and psychological tests. This allowed new interpretations to the index of reliability. Cronbach had created this formula which could be applied throughout a variety of tests and other measurement instruments - gaining an enormous amount of popularity among practitioners.
Cronbach's Alpha provided a measure of reliability from a single test administration thus showing that on repeated occasions, or even other parallel forms of testing, were not needed to estimate a test's consistency (this followed closely from the works of Kuder and Richardson). The Alpha is useful because not only is it easily calculated, but it is also quite general and can be applied universally - for example: dichotomously scored multiple-choice items or polytimous attitude scales.
The generalizability theory (the "G" theory)
As Cronbach’s work progressed on reliability during the 1950s and 1960s it led to his work on the generalizability theoryGeneralizability theory
Generalizability theory, or G Theory, is a statistical framework for conceptualizing, investigating, and designing reliable observations. It is used to determine the reliability of measurements under specific conditions. It is particularly useful for assessing the reliability of performance...
. He began his work with the aim to produce a handbook on measurement - allowing people to apply mathematical concepts to transform one’s behaviours and events into quantitative results. Cronbach believed that there were two flaws in the concept of taking observed test scores into true score and error components: he believed that true scores were "ill-defined" and errors were "all-inclusive". The Generalizability theory addresses the question of the relative influence on test performance based on different aspects of how tests are being administered to people. A question that would be addressed, for example, would be: "will students perform consistently on different occasions?"
The Generalizability theory expanded when Cronbach became concerned that an undifferentiated error term covered up information about systematic variations which could be important in terms of test performance. With this in mind, he teamed up with two other members and developed a "random model" (introduced by a statistician R.A. Fisher) where he was determined to figure out the complexities of error variance. This "G" theory thus provided a combination of the psychological with the mathematical producing a comprehensive framework and statistical model which identified sources of measurement error.
Cronbach's theory goes beyond simply examining consistency in a student’s relative standing in distribution – it recognizes and acknowledges that the particular item used in any given test is only a small indicator from a wider domain of knowledge. Only such extensions to reliability investigations were made possible by the Generalizability theory - which allowed researchers to address more realistic educational problems, and encouraged researchers to place substantial considerations when they made inquires to demonstrate that validity is important especially when evaluating information extracted from test scores.
However, Cronbach's work on validity was no less important nor influential - with the help from Paul Meehl, he placed the concept of validity theory in the centre of educational and psychological testing. Cronbach & Meehl believed that "...it [is]imperative that psychologists make a place for [advocating construct validity] in their methodological thinking, so that its rationale, its scientific legitimacy, and its dangers may become explicit and familiar. This would be preferable to the widespread current tendency to engage in what actually amounts to construct validation research and use of constructs in practical testing, while talking an "operational" methodology which, if adopted, would force research into a mold it does not fit." Cronbach acknowledged reliability as an important characteristic of a test, but believed that reliability and validity went hand-in-hand,and at times, 'trade-offs' were necessary in order to improve reliability. The paper, Construct Validity in Psychological Tests, compiled by both Cronbach and Meehl, represents their research efforts for over 50 years on validity.
External links
- Construct Validity in Psychological Tests, classic text by Cronbach and Paul E. Meehl 1955
- Two Disciplines of Scientific Psychology essay by Cronbach, 1957
- Stanford Memorial Resolution about Lee Cronbach