Bloom, B.S. (1956). Taxonomy of Educational Objectives; the Classification of Educational Goals,. New York: Longmans, Green; 1956.

• Anderson, L.W. and Krathwohl, D.R. (2001). A taxonomy for learning, teaching, and assessing: A revision of Bloom’s taxonomy of educational objectives. New York, NY: Longman.
• Dave, R.H. (1975). Developing and Writing Behavioural Objectives. (R.J. Armstrong, ed.) Educational Innovators Press
• Harrow, A. (1972) A Taxonomy of The Psychomotor Domain: A Guide for Developing Behavior. London: Longman
• Krathwohl, D., Bloom, B., and Masia, B. (1964). Taxonomy of Educational Objectives: The Classification of Educational Goals – Handbook II: Affective Domain. New York: David McKay Company
• Miller, H. (1990) The Assessment of Clinical Skills/Competence/Performance. Acad Med 65(9):S63-S67.
• Simpson, E.J. (1972) The Classification of Educational Objectives in the Psychomotor Domain. 3(3):43-56.

Dr. French sees that Richard is excited about the opportunity to intubate the patient, but he is unable to assess, based on his question, whether Richard truly does not understand the indications for intubation or whether he simply gave an excited response.  After further questioning, he determines that Richard can recite some of the indications for intubation, but he cannot adequately apply them to patient scenarios.

Dr. French has seen this same situation each academic year. He knows that Richard just completed an airway workshop during intern orientation. Dr. French decides that he should review the airway workshop curriculum to determine if it could be improved.

Dr. French finds that much of the current curriculum focuses on the motor skills required for intubating and the “difficult airway” algorithm.  Dr. French is unable to find any actual learning objectives for the current airway course. The current curriculum has a didactic lecture, which reviews the indications for intubation at the beginning of the workshop. The workshop also includes a multiple choice question (MCQ) post-workshop test that also includes questions on the indications for intubation. Dr. French knows that all the interns passed the MCQ test.

Dr. French can’t put his finger on why Richard is not performing as well as he would like. He wonders how he can revise the current airway course to produce a more skilled PGY-1.

Bloom’s Taxonomy is a theoretical framework authored by Benjamin S. Bloom and colleges in the 1950s as a means of organizing and classifying higher education learning objectives and assessment.¹ It serves as one of several conceptual frameworks for the acquisition of knowledge and skills.

When one discusses Bloom’s taxonomy, most are referring to the taxonomy for the original, knowledge-based, cognitive domain. Bloom classified this domain into six hierarchical categories. The original cognitive taxonomy has evolved over time. Anderson proposed the following hierarchical order in 2001³:

1. Remembering: ability to recall facts
2. Understanding: demonstrating comprehension
3. Applying: application on knowledge to new tasks
4. Analyzing: the ability to separate a concept into its components and thus better understanding its organization and structure
5. Evaluating: judging the merits of ideas and components
6. Synthesizing/Creating: creating new structures/ideas from the parts of others learned

Original conference participants and students later published two additional taxonomies for the affective/emotional and psychomotor domains.²

Bloom’s Taxonomy is not the sole work of Benjamin Bloom. It is the result of a series of higher educational conferences that focused on improving communication of and structure for educational objectives and assessments.  The taxonomy established a hierarchy that elevated more advanced higher-order learning objectives and goals above the basics of understanding and remembering.

The original taxonomy, published in Bloom’s 1956 work Taxonomy of Educational Objectives, included the following categories, in the following order: knowledge, comprehension, application, analysis, synthesis, and evaluation. Since this original work, conference participants and others have developed several revisions of the taxonomy. As described in the Overview, Anderson and Krathwohl published the currently used taxonomy, in 2001.

In addition, both affective and psychomotor taxonomies have been added. The original working group responsible for the cognitive objectives in 1956 developed the affective/emotional hierarchical categories. The affective hierarchical taxonomy is as follows:⁴

1. Receiving: acknowledge and attention to knowledge
2. Responding: interacting with learning environment in an appropriate manner
3. Valuing: applying worth or value to specific components learned
4. Organizing: ability to prioritize, compare, and evaluate a topic resulting in organization
5. Characterizing (Internalizing): the ability to use organized value systems to create a pattern of behavior

The final addition was a psychomotor objectives taxonomy. Publications from the original conference did not include this taxonomy, due to a lack of focus on skills-based education.  There are several published versions of psychomotor taxonomies, each differing slightly, but the original taxonomy published by Simpson included the following classifications:⁵

1. Perception: adjust behavior in response to environmental/external clues
2. Set (emotional/physical readiness): demonstration of the willingness and readiness to learn
3. Guided response: ability to perform a trained response to a stimuli often previously demonstrated for the learner
4. Mechanism: this is basic proficiency where the learner can perform habitual and learned responses proficiently
5. Complex overt response: expert proficiency in terms and/or speed and/or quality of a task or act with perception during performance of the quality
6. Adaptation: familiarity with the task allows the learner to adapt portions of the task to specific situations
7. Origination: mastery of the task allows the learner to create new movements and create new routines, teaching programs, and designs

Harrow (1972)⁶ and Dave (1975)⁷ also developed taxonomies for psychomotor objectives. Bloom’s taxonomy is one of several frameworks to guide educators in creating learning objectives for an educational endeavor.  The taxonomy provides an important framework for creating tiered objectives within the cognitive, affective, and psychomotor realms of an educational project.  The focus on a hierarchy of goals supports the creation of goals for learners at different levels or evolving learners.  Many publications have produced a set of action verbs associated with each level of objectives to be used when creating educational objectives.  This facilitates the creation of appropriate goals for each level within a given taxonomy by using the appropriate action verbs.

Over time there have been many different interpretations of the original cognitive taxonomy proposed by Bloom in 1956.  Anderson and Krathwohl published the most significant and accepted revisions in 2001.³ Anderson was a student of Bloom’s and Krathwohl was one of the authors of the original work. The key differences between the original and modern taxonomy were the revision to action verbs from nouns and the switch between the fifth and sixth objective.  This revision also added a second dimension to the cognitive taxonomy with levels of knowledge in addition to the hierarchy of cognitive objectives.  These levels of knowledge included factual, conceptual, procedural and metacognitive.

Likely based on the hierarchical framework of Bloom’s taxonomy, Miller created a framework specifically designed for medical education clinical competency objectives often referred to as Miller’s pyramid.⁸  This hierarchy begins with basic objectives categorized as “knows” (knowledge) and “knows how” (how to apply knowledge) objectives and then moves into application objectives of “shows” (shows how to apply knowledge) and “does” (applies knowledge in practice).  In practice-based fields, lower level knowledge objectives are often required before higher-level application based objectives can be attained.  The pyramid keeps a focus on the overall goal of medical education, which is to create competent practicing physicians who must function in the “does” domain during patient care.

In addition to the creation of learning objectives, the Bloom’s taxonomy assists in developing instructional methods, assessments, and program evaluations. Often educators create higher level educational goals for a course, but only assess lower level goals. The most common scenario is the use of a multiple choice test for student assessment.  This tool functions well to assess remembering, but fails to assess the higher level goals of evaluating and synthesizing. The level of assessment should match the level of the stated goals for an educational activity.

In addition to matching assessment methods to learning objectives, the taxonomy and Miller’s pyramid can help to decide the instructional methods that should be used.  For instance, if one is trying to teach psychomotor skills or higher-level Miller “does” skills, one should match the instructional methods accordingly. In this case, lectures or other passive learning sessions may not be appropriate; rather, instructing and assessing with simulation or standardized patients might be more appropriate.

Adams, N.E. (2015) Bloom’s taxonomy of cognitive learning objectives. J Med Libr Assoc. 103(3): 152–153.

This article provides short and precise examples of each level considered in the classification. The author concludes that this tool is helpful in two important ways: 1) helps the instructor to think of learning objectives in behavioral terms and 2) forces us to include learning objectives that require higher levels of cognitive skills. If one combines both benefits, it will lead to a deeper learning and transfer of knowledge and skills to a greater variety of tasks and contexts.

Phillips, A.W., Smith, S.G., Straus, C. (2013). Driving Deeper Learning by Assessment: An Adaptation of the Revised Bloom’s Taxonomy for Medical Imaging in Gross Anatomy. Acad Radiol. 20:784–789  

Using Bloom’s taxonomy, a group of radiologists and anatomists prepared different types of questions that assessed different hierarchical categories. As they hypothesized, they found that there was an inverse relationship between a student’s score and the level of the cognitive domain tested by the question, supporting the existence of discrete hierarchical levels of cognition.

Larkin, B.G. and Burton, K.J. (2008) Evaluating a Case Study Using Bloom’s Taxonomy of Education. AORN J 88:390-402

Authors took a near miss case in a postoperative unit in a large trauma center and, using Bloom’s taxonomy. They designed a workshop with clear and explicit educational objectives. They observed that the objectives helped the clinical team identify gaps in communication.

Zeng, A.Y., Lawhorn, J.K,  Lumley, T., Freeman, S. (2008). Application of Bloom’s Taxonomy Debunks the “MCAT Myth. Science. 319(5862):414-5.

The initial hypothesis was that the Medical College Admission Test (MCAT) used a larger quantity of higher order cognitive questions than other tests. Comparing six different tests, including MCAT, they found no difference between the number of questions assessing lower levels of knowledge and those evaluating higher levels, including none assessing synthesis and evaluation levels.

Many of the limitations or criticism of Bloom’s Taxonomy stem from the original work.  Such criticisms included the lack of a separate knowledge hierarchy within the cognitive objectives, the original omission of understanding as a level of the cognitive hierarchy, and the order of the hierarchy.  These issues have been largely addressed by the revisions in 2001.

The other main criticisms revolve around the universal adoptions of objective based learning and assessment, without solid evidence behind the taxonomy.  Some feel that the use of objective based learning is an oversimplification of education programing. It prevents viewing the education program as whole entity; instead it separates it into component pieces. In general, the taxonomy serves as a means for creation, evaluation, and revision of teaching objectives in a common and defined language.

Often higher-level objectives or assessments are desired but not feasible.  In addition, many critique Bloom’s original work, stating that achieving lower level learning objectives is not always necessary before achieving higher level learning objectives. This is especially true due to advances in technology the reduce the need for certain knowledge prior to practice.

Finally, many criticize the lack of evidence behind the taxonomy.  The initial taxonomy and subsequent revisions are mostly theoretical and based on expert opinion from those within the Bloom school of thought. Though most agree that there are separate realms of motor/practice-based learning and knowledge based learning, there is no solid evidence to support the separate domains of the taxonomy or specific organization of the hierarchy in education and outcomes.

Dr. French begins revising the airway course curriculum. He understands that Richard’s knowledge deficit lies in the higher end cognitive domain (applying, analyzing, evaluating, and synthesizing), or in the “shows” or “does” objectives in the Miller pyramid of medical education.  Therefore, he must create objectives and use teaching methods and assessment tools aimed at this level of learning.

He first creates the objective: the PGY-1 residents will correctly identify five clinical scenarios in which patients require endotracheal intubation.  In order to teach this objective he builds on the current curriculum.  He decides to keep the lecture format for the purpose of teaching the basic “remembering” type knowledge objectives.  He then creates a series of video clinical vignettes with actors; learners are forced a decision regarding whether intubation.  The scenarios include vital signs, blood gas results, and any physical exam findings/radiographic information that are needed.

Dr. French gives the lecture, leads the residents in a small group discussion about the indications for intubation, and then challenges them with the video clinical vignettes.

Dr. French also must assess the residents’ new knowledge and skills. He wants to ensure that the students have moved beyond the knowledge objectives and are able to apply their knowledge (Miller’s “does”). The current methods focus only on techniques and difficult airway scenarios.  Dr. French adds a few additional scenarios and alters some of the current scenarios to focus on the decision of whether to intubate; he even includes some cases in which the patient should not be intubated.

Dr. French creates a specific assessment checklist tool for each scenario, focusing on the levels of cognitive objectives including:

1. Learner voices the specific indication for intubation (understanding/remembering)
2. Learner collects the proper information needed to make the decision to intubate (applying, analyzing)
3. Learner correctly interprets the information gathered (analyzing, evaluating)
4. Learner makes the correct decision to intubate for the correct reasons (synthesizing)

After application of his new simulation based didactics focusing on indications for intubation, Dr. French is happy to find that in Richard is able to make appropriate decisions about whether to intubate a patient in the subsequent months and years.