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B. S. Bloom (1913–1999)

Renowned as the architect of the taxonomy of educational objectives and famous for his work on mastery learning, Benjamin S. Bloom was a true educational researcher, who thrived on questions to guide his inquiry. His research revolved around the following queries.

  • What is the variety of educational objectives that can (and perhaps should) be taught in school?
  • To what extent are human characteristics such as intelligence and motivation fixed at birth and to what extent can they be modified by experience?
  • How can one teach entire classrooms of students so that the results approximate what can be achieved in one-to-one tutoring?
  • How is it that certain individuals reach the highest level of accomplishment in their chosen fields?

These are but some of the questions that Bloom asked, and answered, during a career that spanned five decades, the vast majority of which was spent on the faculty of the University of Chicago.

Bloom was born in Lansford, Pennsylvania, of Russian immigrant parents. His father was a picture framer and his mother a housewife. Bloom attended public schools in Lansford, graduating in 1931 as class valedictorian. In the fall of 1931 he enrolled at the Pennsylvania State University, completing his B.A. and M.A. degrees in psychology in four years.

Following college graduation, he was employed for a year as a research worker with the Pennsylvania State Relief Organization. He then moved to Washington, D.C., where he took a similar position with the American Youth Commission. It was while working at the commission that he met Ralph W. Tyler. Bloom was so impressed with Tyler that he decided to study with him. He began his doctoral studies at Chicago in the summer of 1939. That summer he met his future wife, Sophie, and they were married a year later.

While completing his doctoral program, Bloom was a research assistant in the Office of the University's Board of Examinations under Tyler's supervision. He received his Ph.D. in 1942, and remained with the Board of Examinations until 1959. In 1948, Bloom convened a meeting of college and university examiners throughout the country to discuss the possibility of designing a common framework for classifying the wide variety of intended learning outcomes that the examiners routinely encountered. Eight years later The Taxonomy of Educational Objectives, The Classification of Educational Goals, Hand-book I: The Cognitive Domain was published. By the late 1960s, it became known simply as Bloom's taxonomy.

The majority of Bloom's writings during his years with the board (and concurrently as a junior faculty member in the Department of Education) focused on testing, measurement, and evaluation. Then, in 1959 to 1960, he left his position with the board and spent a year at the Center for Advanced Study in Behavioral Sciences at Stanford University in Palo Alto, California.

During his stay at the center, Bloom began work on what was to become his work Stability and Change in Human Characteristics. The book consisted primarily of an extensive review of research in several areas (e.g., intelligence, achievement, and personality). Based on this review, Bloom suggested that the ability of environmental factors to influence change in human characteristics decreases over time, as the characteristics become more stable. He discussed his findings with U.S. President Lyndon B. Johnson, and his testimony before Congress played a large part in the federal Head Start program in 1965. The program became an important part of Johnson's Great Society, and has enjoyed bipartisan congressional support since then.

In 1968 Bloom published a small paper titled "Learning for Mastery," which had great significance in the field. His central thesis was that most students (perhaps more than 90%) could master what they were expected to learn in school, and it was the task of teachers to provide the quality of instruction that would produce these results. Critical elements of this quality of instruction were (1) clearly communicating the learning expectations; (2) giving students specific feedback as to their progress in achieving them; and (3) providing additional time and help as needed by students.

During the 1970s Bloom worked at incorporating this thesis into a full-blown theory of school learning and challenging educators to solve what he termed in 1984 the "two sigma problem." Based on available data, Bloom argued that the average student who received tutoring scored two standard deviations higher on standardized achievement tests than average student who received traditional group-based instruction. Because the Greek symbol sigma is used to denote the standard deviation of a population, the problem of finding ways to design and deliver group-based instruction that was as effective as one-to-one tutoring was known as the two sigma problem.

In 1984 Bloom published his last major study, in which he identified and described the processes by which those individuals who reached the highest levels of accomplishment in their chosen fields (e.g., concert pianists, research mathematicians, Olympic swimmers) were able to develop their capabilities so fully. The results suggested that the initial characteristics (or gifts) of the individuals would not by themselves enable extraordinary levels of accomplishment unless there is a long and intensive process of encouragement, nurturing, and training.

Bloom will be remembered for introducing educators to the world of possibilities: There are educational objectives that lie beyond rote memorization. All students, not just a select group, can learn and learn well. Talent is not something to be found in the few; it is to be developed in the many. His unflagging belief in the power of education, both for the welfare of individuals and for the betterment of society; the frameworks he developed for thinking about and talking about educational issues and problems; the Taxonomy; his theory of school learning; and his stages of talent development are his enduring legacy to education.


BLOOM, BENJAMIN S. 1956. Taxonomy of Educational Objectives, Handbook 1: The Cognitive Domain. New York: Longman.

BLOOM, BENJAMIN S. 1964. Stability and Change in Human Characteristics. New York: Wiley.

BLOOM, BENJAMIN S. 1968. "Learning for Mastery." UCLA Evaluation Comment 1 (2):1–8.

BLOOM, BENJAMIN S. 1976. Human Characteristics and School Learning. New York: McGraw-Hill.

BLOOM, BENJAMIN S. 1984. "The 2 Sigma Problem: The Search for Methods of Group Instruction as Effective as One-to-One Tutoring." Educational Researcher 13 (6):4–16.

BLOOM, BENJAMIN S. 1985. Developing Talent in Young People. New York: Ballentine.


Additional topics

Education - Free Encyclopedia Search EngineEducation Encyclopedia: AACSB International - Program to Septima Poinsette Clark (1898–1987)