The trouble with Bloom’s taxonomy

One of the cornerstones of course design in the e-learning industry is the practice of sequencing the outcomes of curricula, modules and content according to the principles of Bloom’s taxonomy. Instructional designers typically use this theory to expose learners to foundational content first: things that require learners to remember, understand, and apply. As the course progresses, learners are challenged to complete tasks that require progressively higher orders of thinking — as defined by the taxonomy — until they have mastered the material. 

There are some problems with this very popular approach in e-learning. Instructional designers often adopt Bloom’s taxonomy because it is the only scaffolding framework they are taught, or because the verbs translate so nicely into learning technology-based activities. However, Bloom’s taxonomy was never intended to serve as a scaffolding framework, which is likely the reason that it is not a particularly good one.

Bloom’s taxonomy is a theory of assessment, not learning

Benjamin Bloom and his team of cognitive psychologists originally published Taxonomy of Educational Objectives, Handbook 1: Cognitive Domain as the cognitive component of their theory of development in 1956. The original intention was to help educators design assessments that would target several levels of cognitive functioning at the same time, without needing to assess each order of thinking individually. This theory was then revised in 2001 by another team of scholars, led by Lorin Anderson, to create the form of the taxonomy that is widely used today.

Most people consider this revision as primarily a change in the verbs and their order, but the more important shift that happened with Anderson’s version of the taxonomy is its purpose. Whereas Bloom and his associates conceptualised the taxonomy as a framework for designing efficient and effective assessments, Anderson’s version adapts Bloom’s taxonomy to be a theory of teaching and learning. 

Why is this significant? Well, this framework’s original intention was to determine which orders of thinking are tested in a single question, so that questions can be designed to check for knowledge at various orders of thinking at the same time.

An instructional designer can therefore design a question at the Analyse level and, if they did this correctly, they could safely assume that Remember, Understand and Apply will also be tested in that question, and they do not need to set additional questions to test the lower orders. 

This is rather different to how Bloom’s is used by proponents of Anderson’s version, who apply it as a form of scaffolding learning rather than designing assessments. This is an important shift, as learning and assessment are two very different processes. Whereas learning is the process of creating and storing knowledge, concepts and skills, assessment is the process of checking whether the knowledge is stored, and retrieving it. 

What happens when the principles that underpin a theory of assessment are applied as the dominant approach to scaffolding a learning experience? The reality is that sequencing lessons or tasks in a course or module based on the order of thinking that those tasks require is not always the best approach to scaffolding that topic.

Scaffolding and differentiated learning

The concept of scaffolding learning was popularised by the psychologist and social constructivist Lev Vygotsky as part of his theory of the Zone of Proximal Development in 1978. When scaffolding learning, the aim is to provide a learner with just the right amount of support that they need to achieve the next goal in their learning. Not too much assistance, but just enough to get them over the line. This can only be achieved by first checking what the learner already knows, then relating the new content to that existing knowledge, then breaking the content into smaller tasks that challenge the learner to construct new knowledge, all with frequent opportunities for constructive feedback.

As an approach to scaffolding, Bloom’s taxonomy is not immune to the problems that plague the application of any scaffolding framework in e-learning development. For scaffolding to work, the first step must be to check for prior knowledge in order to determine where the first set of scaffolds may be required. In e-learning, this would manifest as the learner first taking a pre-assessment, after which the learning path is differentiated to exclude that which the learner has already mastered. 

If the path is not differentiated, the standard path likely contains too much information for the learner to be challenged to construct learning on their own. Most instructional designers would rather include too much information than risk omitting something important. The result is that the learning material will be designed for the one student that needs the most help, and thereby be inappropriately scaffolded for the majority of the group. It is also likely more didactic than it needs to be. The resulting design therefore actively works against the principles foundational to Vygotsky’s theory, and can no longer be called scaffolding. When students are not challenged, they lose all reason to engage; this is even more true of Gen-Z learners.

When students are not challenged, they lose all reason to engage; this is even more true of Gen Z learners.

With Bloom’s, as with other scaffolding frameworks, the approach can only really be meaningfully applied in e-learning courses if the material is differentiated based on a pre-assessment. However, Bloom’s as a scaffolding framework also poses some fairly unique challenges that are not present in other approaches to scaffolding.

Bloom’s taxonomy is usually not the best way to scaffold a topic

The reality is that sequencing lessons or tasks in a course or module based on the order of thinking that those tasks require is not always the best approach to scaffolding that topic. Consider the below example. I think, depending on their level of understanding of math, most instructional designers would agree that the below module is well-scaffolded:

  • Lesson 1: Use the five rules of exponents
  • Lesson 2: Find the power of a product and a quotient
  • Lesson 3: Simplify exponential expressions

The foundational principles are taught, after which those principles are applied in a slightly more complex type of equation, after which both the principles and the more complex type of equation are applied in a range of even more complex combinations and examples. The lessons certainly increase in difficulty as the module progresses. However, all three lessons operate at the “Apply” level of Bloom’s taxonomy. In many cases, Bloom’s taxonomy is a rather unimportant consideration when scaffolding a module, so if this is an instructional designer’s primary or only approach to scaffolding, they are bound to get it wrong.

Bloom’s taxonomy only works for tightly aligned topics

In addition to the fact that Bloom’s is often not the best approach to scaffolding a module, there are many types of topics to which Bloom’s taxonomy can’t be applied at all, even as a theory of assessment. Bloom’s taxonomy is only appropriate for application to what Roland Case terms “tightly aligned” topics.  When assessing a “tightly aligned” topic using Bloom’s taxonomy, one can assume that anything assessed at the “recall” and “understand” level will also be assessed within the “apply” level. 

Adapted as a theory of learning, this means that if my course has three modules, the same knowledge covered in module 1 and 2 would be relied upon to teach module 3, and therefore if the learner skips modules 1 and 2, they would not be able to understand much of module 3. This can only be true in very specific circumstances, and is contrary to how many instructional designers apply Bloom’s theory today. Consider again our example from earlier:

  • Lesson 1: Use the five rules of exponents
  • Lesson 2: Find the power of a product and a quotient
  • Lesson 3: Simplify exponential expressions

Most if not all of Lesson 3 would deal with problems that a student can only attempt if they had mastered what was taught in Lessons 1 and 2. To these tightly aligned topics, one could (if one were so inclined) successfully apply Bloom’s theory to scaffold the material. However, most topics are not this tightly aligned, and themes and challenges that instructional designers use Bloom’s to scaffold typically relate to one another much more loosely. Therefore, Bloom’s taxonomy cannot be meaningfully applied to that topic, even in the taxonomy’s original format as a theory of assessment.

Where do we go from here?

Although Bloom’s taxonomy is a useful tool for ensuring that all outcomes are assessed efficiently, there are multiple problems with how it is typically being used as a tool for scaffolding in e-learning development:

  1. Any e-learning course that claims to scaffold content (using any framework), but does not differentiate the learning path based on a learner’s prior knowledge, is not scaffolding the content correctly for most learners.
  2. Bloom’s taxonomy was intended as a theory of assessment, rather than a theory of learning. Sequencing lessons and exercises according to the order of thinking that they engage is often not the best approach to scaffolding a topic.
  3. Bloom’s approach to assessment only applies in cases where topics are tightly aligned, and one can assume that learners mastered the outcomes of Lessons 1 and 2 if they successfully master Lesson 3, without ever seeing Lessons 1 and 2.

Does this mean that Bloom’s taxonomy no longer has a place in e-learning? Certainly not. It remains a useful way to think about assessment design, and even for the development of exercises and activities. However, when it comes to scaffolding the content within a programme, course or module, our approach needs to be more robust.

How do you think about scaffolding your learning experiences? Let us know in the comments!


Sources for further reading

  • Anderson, L.W. and Krathwohl, D.R. eds. 2001. A Taxonomy for Learning, Teaching, and Assessing: A Revision of Bloom’s Taxonomy of Educational Objectives. New York: Addison Wesley Longman, Inc.
  • Bloom, B.S. (Ed.) 1956. Taxonomy of Educational Objectives: The classification of educational goals. Handbook 1, Cognitive Domain. New York.
  • Case, Roland. The unfortunate consequences of Bloom’s taxonomy. Social Education, 2013;77(4), 196-200.
  • Gaffney, J.S. and Richard C. Anderson, R.C. (1991). Two-Tiered Scaffolding: Congruent Processes of Teaching and Learning. Center for the Study of Reading.
  • Greenfield, P. M. (1984). A theory of the teacher in the learning activities of everyday life. In B. Rogoff & J. Lave (Eds.), Everyday cognition: Its development in social context (pp. 117-138). Cambridge, MA: Harvard University Press.
  • Silver, D. (2011). Using the ‘Zone’Help Reach Every Learner. Kappa Delta Pi Record, 47(sup1), 28-31.
  • Vygotsky, L. S. (1978). Mind in society: The development of higher psychological processes. Cambridge, MA: Harvard University Press. 
  • Vygotsky, L. S. (1981). The genesis of high mental functions. In J. V. Wertsch (Ed.), The concept of activity in Soviet psychology (pp. 144-188). Armonk, NY: Sharpe.

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