Bloom’s taxonomy

Bloom’s taxonomy, taxonomy of educational objectives, developed in the 1950s by the American educational psychologist Benjamin Bloom, which fostered a common vocabulary for thinking about learning goals. Bloom’s taxonomy engendered a way to align educational goals, curricula, and assessments that are used in schools, and it structured the breadth and depth of the instructional activities and curriculum that teachers provide for students. Few educational theorists or researchers have had as profound an impact on American educational practice as Bloom.

Understanding education and its objectives

Throughout the 20th century, educators explored a variety of different ways to make both explicit and implicit the educational objectives taught by teachers, particularly in early education. In the early 20th century, objectives were referred to as aims or purposes, and in the early 21st century, they evolved into standards. During much of the 20th century, educational reformers who wanted to more clearly describe what teachers should teach began to use the word objectives, which referred to the type of student learning outcomes to be evidenced in classrooms. Bloom’s taxonomy was one of the most significant representations of those learning outcomes.

Bloom’s work was not only in a cognitive taxonomy but also constituted a reform in how teachers thought about the questioning process within the classroom. Indeed, the taxonomy was originally structured as a way of helping faculty members think about the different types of test items that could be used to measure student academic growth. Bloom and a group of assessment experts he assembled began their work in 1949 and completed their efforts in 1956 when they published Taxonomy of Educational Objectives: The Classification of Educational Goals, Handbook 1: Cognitive Domain.

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Bloom’s cognitive domains

Bloom’s cognitive taxonomy originally was represented by six different domain levels: (1) knowledge, (2) comprehension, (3) application, (4) analysis, (5) synthesis, and (6) evaluation. All of the Bloom domains focused on the knowledge and cognitive processes. The American educational psychologist David Krathwohl and some of his associates subsequently focused on the affective domain, which is concerned with student interests, attitudes, and feelings. Another American educational psychologist, Anita Harrow, developed the psychomotor domains, which deal with a wide variety of motor skills. Bloom’s work was most noted for its focus on the cognitive. Bloom became closely associated with the cognitive dimension even though, in subsequent work, he often examined the wide variety of “entry” characteristics (cognitive and affective) that students evidenced when they began their schooling.

Each of Bloom’s cognitive domains enabled educators to begin differentiating the type of content being taught as well as the complexity of the content. The domains are particularly useful for educators who are thinking about the questioning process within the classroom, with questions ranging in complexity from lower-order types of knowledge to higher-order questions that would require more complex and comprehensive thought. Bloom’s taxonomy enabled teachers to think in a structured way about how they question students and deliver content. The taxonomy, in both its original and revised versions, helped teachers understand how to enhance and improve instructional delivery by aligning learning objectives with student assessments and by enhancing the learning goals for students in terms of cognitive complexity.

The following list presents the structure of the original framework, with examples of questions at each of the six domain levels:

1. Knowledge Level: At this level the teacher is attempting to determine whether the students can recognize and recall information. Example: What countries were involved in the War of 1812?
2. Comprehension Level: At this level the teacher wants the students to be able to arrange or, in some way, organize information. Example: In the book Teammates the authors describe Jackie Robinson’s struggles as a baseball player and the way in which Pee Wee Reese publicly defended Robinson. Describe in your own words the struggles that Robinson had and what Reese did to help him succeed as a baseball player.
3. Application Level: At this level the teacher begins to use abstractions to describe particular ideas or situations. Example: What would be the probable influence of a change in temperature on a chemical such as hydrochloric acid?
4. Analysis Level: At this level the teacher begins to examine elements and the relationships between elements or the operating organizational principles undergirding an idea. Example: Describe the way in which slavery contributed to the American Civil War.
5. Synthesis Level: At this level the teacher is beginning to help students put conceptual elements or parts together in some new plan of operation or development of abstract relationships. Example: Formulate a hypothesis about the reasons for South Carolina’s decision to secede from the Union.
6. Evaluation Level: At this level the teacher helps students understand the complexity of ideas so that they can recognize how concepts and facts are either logically consistent or illogically developed. Example: Was it an ethical decision to take to trial the Nazi war criminals and to subsequently put so many of them to death?

Bloom focuses primarily on the cognitive dimension; most teachers rely heavily on the six levels of the cognitive domain to shape the way in which they deliver content in the classroom. Originally Bloom thought about the characteristics that students possess when they enter school, and he divided those characteristics into the affective and the cognitive. From Bloom’s perspective the learning outcomes are a result of the type of learning environment a student is experiencing and the quality of the instruction the teacher is providing. The affective elements included the students’ readiness and motivation to learn; the cognitive characteristics included the prior understandings the students possessed before they entered the classroom. In essence, a student who had an extensive personal vocabulary and came from a reading-rich home environment would be more ready to learn than the student who had been deprived of such opportunities during his preschool years. In the early 21st century, some reformers described this as the “knowledge gap” and specifically highlighted the fact that students from low socioeconomic settings have less access to books and a lower exposure to a rich home vocabulary. In essence, some of Bloom’s original ideas continued to be reinforced in the educational research literature.

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A revision of Bloom’s taxonomy

Many researchers had begun to rethink the way in which educational objectives were presented by teachers, and they developed a revision of Bloom’s taxonomy in 2001. The revised taxonomy was developed by using many of the same processes and approaches that Bloom had used a half century earlier. In the new taxonomy, two dimensions are presented: the knowledge dimension and the cognitive dimension. There are four levels on the knowledge dimension: factual, conceptual, procedural, and metacognitive. There are six levels on the cognitive process dimension: remembering, understanding, applying, analyzing, evaluating, and creating. The new taxonomy enabled teachers to think more in depth about the content that they are teaching and the objectives they are focusing on within the classroom. It allowed teachers to categorize objectives in a more-multidimensional way and to do so in a manner that allows them to see the complex relationships between knowledge and cognitive processes.

The original Bloom’s taxonomy allowed teachers to categorize content and questions at different levels. The new two-dimensional model enabled teachers to see the relationship between and among the objectives for the content being taught and to also examine how that material should be taught and how it might be assessed. By examining both the knowledge level and the cognitive processes, teachers were better equipped to consider the complex nature of the learning process and also better equipped to assess what the students learn.

The new taxonomy did not easily spread among practitioners, in part because most classroom teachers remained unfamiliar with the new taxonomic approach and because many professional development experts (including those in teacher-education institutions) continued to rely on the original taxonomy. The new model was in many ways just as significant as the original taxonomy. The original approach provided a structure for how people thought about facts, concepts, and generalizations and offered a common language for thinking about and communicating educational objectives. In essence, it helped teachers think more clearly about the structure and nature of knowledge. The new taxonomy helped teachers see how complex knowledge really is.