Bloom’s Taxonomy is a hierarchy of cognitive processes ranging from the simple to the complex.

To master those higher up you must first master those lower down.

The processes to which it refers can be used with almost any type of content, with the caveat that their use will be cognitive in nature (rather than affective or psychomotor. So if you’re a teacher of a maths, modern foreign languages, a practical subject or teach practical areas of the curriculum, Bloom’s has some relevance, but not as much).

As a reminder, here’s what the taxonomy looks like:

• Level 1 – Knowledge
• Level 2 – Comprehension
• Level 3 – Application
• Level 4 – Analysis
• Level 5 – Synthesis
• Level 6 – Evaluation

Now, let’s dig down into each level and see what’s going on under the bonnet.

Level 1: Knowledge

Level 1, knowledge, is the simplest. Here we are concerned with recall, memory and knowing.

This is about gaining information and making it a part of our minds, such that we can call on it and use it when thinking and doing at a later date.

For example, we would expect learners to know what a word means before expecting them to be able to do anything with that word.

Level 2: Comprehension

Level 2, comprehension, is about understanding what we know.

So, for example, I might be able to recall the definition of a word, but that does not necessarily mean that I understand the definition or how the word can be used in different contexts.

Comprehension centres on learners being able to demonstrate an understanding of the facts they know (which they can remember).

Immediately then, we can see two important features inherent to the taxonomy.

The first is that, as we said previously, there is a sense of development running through the levels.

This is why the taxonomy promotes mastery learning.

To be able to operate successfully at any given level, you must also be able to work successfully at the preceding level.

Thus, comprehension relies on prior knowledge, just as the ability to apply understanding rests on comprehension and knowledge of the original facts.

Even though the taxonomy splits cognitive processes into a series of separate categories, there remains the clear sense that these processes do not exist independently of one another.

Rather, they are interlinked and intertwined.

The taxonomy is a delineation, yes, but so too is it akin to a building, in which the top levels can only exist if the bottom levels are already in place.

The second is that the taxonomy provides a framework that mirrors much of our experience of learning.

This is to be hoped if it is to be effective. But let us just consider the point briefly.

Think back to when you first encountered something with which you were not familiar.

An idea perhaps, or a piece of information.

Chances are that your natural inclination was to first try to understand what the thing in question was.

And, to do this, you needed to know it – to be able to remember it.

Now, contrast this experience to a hypothetical individual who has no capacity to remember.

Such an individual would not be able to understand any ideas or any information to which they were exposed because they would not be able to establish a starting point of remembrance from which to cast off.

Their mind would not be able to assimilate the knowledge necessary for understanding to develop.

This further demonstrates how the taxonomy reflects the lived experience of learning.

(As a side point, our hypothetical individual would probably struggle ever to become a person, given as how our sense of self rests in large part on the ability to remember things concerning who we are and what we have done.)

Level 3: Application

After comprehension we have level 3, application.

Here, we are concerned with how a learner can take their knowledge and understanding of something and apply it to novel situations such as problems.

The aim is to use the foundations that have been established to deal with things of which we, as yet, have no knowledge or experience.

In the classroom, this often sees learners answering questions or solving problems once they have secured a basic level of understanding concerning a given topic.

Level 4: Analysis

Level 4, analysis, takes things a step further.

It involves us being able to take apart that with which we are presented to show relationships, motives, causes, connections, and inner workings.

To be able to analyse something, we need to be able to apply that which we know and understand.

If we haven’t mastered, at least to some degree, the process of application, we will find it hard to effectively analyse that with which we are presented.

For example, we might ask a group of learners to analyse how an engine works.

To do this, they would need to examine the engine in detail, looking at how the parts connect, looking at what causes what, and how the different parts influence and interact with one another.

Without a prior knowledge and understanding of engines and engine parts, a knowledge and understanding that learners feel confident applying to different situations, this task will be very difficult.

Learners might be able to point to how things within the engine interconnect or affect each other – they might even be able to describe this in some rudimentary way – but without a degree of mastery of the underlying facts and principles, they will struggle to accurately analyse the structure of the engine in any depth.

Once again, this illustrates the way in which the levels of the taxonomy are interlinked and how successful mastery relies on firm foundations.

Level 5: Synthesis

Moving on, we have level 5, synthesis.

This involves the creation of that which is new.

It could be completely new, or it could be a development of something already existing.

In this sense, the category covers quite a wide range of cognitive processes.

In the context of analysis, the intellectual development here stems from the fact that a learner needs to be able to effectively analyse the structure and make-up of a given item if they are to create something that reflects this, utilises it or goes beyond it.

Let us continue with our engine example to illustrate the point.

Having successfully analysed the structure of the engine, learners are now asked to design an improvement to make the engine more efficient.

The word ‘design’ here signifies that an act of synthesis is being requested.

And that act cannot be successfully completed unless learners are first able to analyse the structure of the existing engine.

This is because any improvement they design must take account of that which already exists.

Thus, we see the central feature of all synthesis-based cognitive acts: the movement from what is to what could be.

Successful synthesis relies on an analytical understanding of what has come first.

Another example further demonstrates the point.

If we ask a learner to create an argument supporting the abolition of the death penalty in those countries where it remains in force, we are expecting that learner to have some degree of analytical understanding of what constitutes an argument as well as ideas surrounding the death penalty itself.

If learners are unable to analyse why the death penalty still exists and why many argue that it should not, then they will not have the tools necessary with which to construct their own argument regarding its abolition.

Once again, the metaphor of a building is helpful.

It is easier to build on firm foundations than it is on shaky ones.

In the latter case, we are severely limited in the scope of what we can do.

And, crucially, there is a higher likelihood that our edifice may collapse if it is put under any sort of pressure.

This is exactly what happens in the classroom, though not necessarily to bad effect.

For example, a learner who has failed to grasp the way in which our engine works may produce a design which, when put into practice, would quickly fail.

Now, this would demonstrate to us as the teacher that the learner does not have a sufficient grasp of the engine’s structure to create a successful improvement.

But it would also give the learner an important learning opportunity.

When played out, either in practice or through a model, they would see the failure of their design and then be compelled to ask: Why did it go wrong?

To answer the question, they would need to return to the drawing board and compare what they did with what they know about the engine.

However, this knowledge would now be supplemented by the knowledge of their design’s failure!

From here they can begin to deduce further information about the engine’s structure, by comparing what they thought they understood with what happened when they tried to build on their understanding.

(This is trial and error in action. Here, the learner pings between synthesis and analysis, until they have sufficient analytical understanding to successfully complete the synthesis.)

High-quality application of Bloom’s Taxonomy by teachers involves the creation of an environment in which learners are encouraged to see their mistakes as an essential step on the path to mastery.

A brief detour to reinforce this point before we turn to level 6, evaluation.

When developing the electric lightbulb, Thomas Edison went through hundreds of iterations with his team of workers.

Each one failed.

But each provided an insight into why success was not forthcoming.

Eventually, Edison and his team were able to produce a working lightbulb.

They had mastered the process.

We might look at this as an incessant, repetitive journey between analysis and synthesis.

Working with incomplete knowledge, Edison and his team continually attempted to create something based on their analysis of what they did know and understand.

Each failure indicated the incompleteness of their analysis.

Therefore, on each occasion, they had to return to this and see what they could glean through a comparison between what they did know and understand and what information had been provided by the failure.

We can safely assume that, by the end of the process and the creation of the lightbulb prototype that worked, the analytical understanding possessed by Edison and his team was far in advance of that with which they had started.

And it was this, in large part, that would have enabled them to create (synthesise) a solution to their problem.

This process can be put in simpler terms: trial and error.

So often, the process of synthesis actually serves to enhance our analytical understanding because the things that we create are less perfect than we expect them to be.

Level 6: Evaluation

Now let us complete our initial journey through the taxonomy by looking at level 6, evaluation.

To be able to assess, judge or rank an item or series of items successfully, we need to:

• Know what they are
• Understand them
• Be able to apply our understanding
• Be able to analyse the nature of the things in question
• And be able to combine or use what we know to create something new (This isn’t always necessary. In many cases, we can jump from analysis to evaluation. Which is perhaps why subsequent research has suggested swapping round the top two levels of the taxonomy, though I won’t get into that here.)

Only with this prerequisite knowledge and understanding will we be able to provide a thorough, nuanced judgement.

Or, to put it another way, a masterful one.

A few points arise from this.

First, evaluation, like the preceding levels, can be done usefully without being perfect.

If, for example, we ask learners to assess whether it would be a good idea to ban homework, we can reasonably expect them to give an interesting, relatively well-conceived response, even if this judgement would not be marked by absolute mastery of the topic.

Similarly, we might expect that all learners in a class could reach a level of evaluation regarding a given topic, but that the extent and quality of this evaluation will vary depending on the prior knowledge and understanding of the learners in question.

A learner who knows more and understands more has far more on which they can call to make a judgement than a learner who knows less and understands less.

In the case of the latter, judgement might be difficult to achieve, it might be general and vague, or it might rest on knowledge and understanding taken from somewhere else (as, for example, when a learner attempts to rely on their knowledge of a related topic to make a judgement about the present topic, of which they know less).

Let us briefly travel into the world of medicine to illustrate what we are saying.

Imagine that we have a minor ailment.

We attend our local GP’s surgery and see the doctor.

The doctor examines us to assess the nature of our complaint. In so doing, they call on their extensive yet general knowledge and understanding of medicine.

Two paths may then follow.

In the first case, the doctor’s judgement proves correct.

They prescribe a course of treatment, and, within a week, we feel much better.

Here, the doctor’s knowledge and understanding (levels 1-5) is sufficient to warrant a successful, masterly diagnosis (assessment) of the problem, along with a concomitant treatment.

In the second case, we return to the doctor after a week to tell them that nothing has changed.

The treatment has had no impact.

The doctor might tell us to persist a while longer, or they might refer us to a specialist.

Why?

Because a specialist possesses a depth of knowledge and understanding concerning the area in question far beyond that required to be a successful general practitioner.

The GP, having made the best assessment of which they are capable, given the knowledge and understanding they possess, acknowledges that someone with greater expertise is better placed to accurately assess the nature of the problem.

The specialist is that person.

Because they have chosen to specialise, they have been able to focus their mind on a particular area, gaining an expert’s knowledge and understanding which, in turn, allows them to make expert judgements.

Of course, it does not follow that their judgements will always be correct.

But it does follow that they are better placed to make correct judgements.

A Continuum of Evaluation

This vignette illustrates how effective evaluation rests on mastery of prior knowledge and understanding as well as the fact that effective evaluation is a continuum along which different learners can sit at different times.

In short, you do not have to have complete mastery of all the preceding levels to give a judgement, but the greater your mastery, the better your judgement is likely to be.

This demonstrates that not all judgements need to be masterful but that better judgements will be closer towards mastery then poorer judgements.

I have stressed this point, along with that about synthesis and trial and error, because some may argue that the higher levels of the taxonomy are inaccessible to less-able learners.

Personally, I disagree.

My reasoning is not that every learner will be able to synthesise and evaluate to the same extent.

Clearly, they won’t (as has been implicitly argued above).

But all learners will be able to access synthesis and evaluation to some degree, using their prior knowledge and understanding to create new things or pass judgements.

These may not work or may face criticism. But so what?

That’s good!

Because it is in this erring that learning takes place.

And that is why I would suggest that we think of the challenge inherent in Bloom’s Taxonomy as being open to all, with that challenge being met and experienced in different ways.

For example, a very able learner may produce a detailed evaluative summary of a piece of work they have done.

This would be challenging in itself and we could further challenge them be questioning them about the validity of their judgement.

A less-able learner may produce a quite general assessment of their work, based on their limited understanding.

However, developing this judgement will still have been a challenge.

And we can further push their thinking by asking them questions that cause them to revisit their knowledge and understanding at the level of application or analysis.

This will help them sharpen their abilities, leading to a revised judgement resting on a deeper and more detailed knowledge and understanding of the topic in question.

This leads us to our final point, echoing something we said earlier about synthesis.

Evaluation can produce a useful feedback loop, just the same as the synthesis-analysis loop outlined above.

If we make a judgement and then find that the judgement does not hold, does not fit with information of which we were previously unaware (or which we overlooked), or is challenged on grounds we had not considered, then we have information on which we can act to change things.

In the classroom, a failed judgement is not a failure in itself.

It is only a failure if we seek to do nothing with it.

If, on the other hand, we use the information provided to go back and look again, then we are learning.

For example, a learner might produce an assessment of Ted Hughes’s use of imagery in a particular poem.

During the lesson we might read through this and then pose the learner a question that challenges them to analyse an aspect of the poem they have overlooked.

(Our question is based on our own assessment of the learner’s judgement.)

By going back to re-examine the poem, directed by our questioning, the learner further develops their analytical understanding leading, in turn, to a higher quality judgement second time around.

This demonstrates how evaluation can be the basis for a trial-and-error feedback loop in the same way as synthesis.

You might even argue that, in many cases, the two levels are intertwined (we create and evaluate at the same time, using the latter as part of the former, see where we went wrong, and then return to analysis before trying again).