During my conversations, interactions, designing, and planning with  teachers and lead teachers in the past decade, one obscure thing stands out in their minds: Bloom’s Taxonomy of cognitive process. This is what they articulate knowledge of. Many may have heard it in the staff room, been exposed to it in  professional development workshops, read it online or in a reference book, or perhaps even studied it during their college years. Many also may have used Bloom’s cognitive nouns and verbs to guide  their lesson planning, instructional practice, and even their assessments. Still, few know that Bloom’s Taxonomy has been updated in 2000. And very few know about Bloom’s knowledge dimensions (factual, conceptual, procedural, and metacognitive). Whatever their level of knowledge of Bloom’s taxonomy, teachers recognize it directly and can even relate their teaching strategies if asked to categorize their practice and assessment.

This is really exciting as it holds real potentials to improve students achievement, but in the education domain one needs to know what works well and what does not work so well, in practice. If teachers want teaching clarity, that is making learning targets and success criteria clear for learners and teachers themselves, if teachers want learners to take more control over their learning,  and if teachers need to systematically use differentiation in their teaching, the taxonomy needs to be clear for both teachers and learners. The teacher, the learner, the tasks, and the assessment should all be clearly informed by the taxonomy.  This clarity is where Bloom’s taxonomy fails. The levels of cognitive processes in Bloom’s taxonomy, and their respective action verbs do not help teachers set clear, measurable learning targets, do no help teachers set learning activities that can meet the learning targets, and do not help learners recognize and articulate the cognitive processes they are involved in. Finally, Bloom’s taxonomy does not provide a whole school framework and common language to systemize instructional routines and assessments, including learner self-assessment. I have rarely, if ever, seen teachers who have designed, planned and delivered lessons with clarity informed by Bloom’s, nor have I seen learners who clearly know what cognitive effort a task entails or success criteria it needs in terms of Bloom’s. Pam Hook  says:

The taxonomy was published in 1956, has sold over a million copies, has been translated into several languages, and has been cited thousands of times.

The Bloom taxonomy has been extensively used in teacher education to suggest learning and teaching strategies, has formed the basis of many tests developed by teachers (at least while they were in teacher training), and has been used to evaluate many tests.

It is thus remarkable that the taxonomy has been subject to so little research or evaluation.

Most of the evaluations are philosophical treatises noting, among other criticisms, that there is no evidence for the invariance of these stages, or claiming that the taxonomy is not based on any known theory of learning or teaching.

The SOLO taxonomy (Structure of Observed Learning Outcomes),devised by Collis  Biggs (1982), is divided into several levels  produced by students in terms of their complexity. The name itself reveals its function. The taxonomy is a structure, that is it has a form, and this form permeates throughout all knowledge levels. The taxonomy focuses on clarity since it seeks to make the learning outcomes observable by teachers and learners, unlike Bloom’s cognitive taxonomy which was devised for educational administrators.

The following is taken from Pam Hook’s wiki “The Learning Process – How Do You Know You are Learning?”

  • At the pre-structural level of understanding, the student response shows they have missed the point of the new learning.
  • At the uni-structural level, the learning outcome shows understanding of one aspect of the task, but this understanding is limited. For example, the student can label, name, define, identify or follow a simple procedure.
  • At the multi-structural level, several aspects of the task are understood but their relationship to each other, and the whole is missed. For example the student can list, define, describe, combine, match, or do algorithms.
  • At the relational level, the ideas are linked, and provide a coherent understanding of the whole. Student learning outcomes show evidence of comparison, causal thinking, classification, sequencing, analysis, part whole thinking, analogy, application and the formulation of questions.
  • At the extended abstract level, understanding at the relational level is re-thought at a higher level of abstraction, it is transferred to another context. Student learning outcomes at the extended abstract level show prediction, generalisation, evaluation, theorising, hypothesising, creation, and or reflection.


Here’s a newer representation of SOLO using the house as a metaphor.


SOLO included declarative and functioning learning verbs


Source: Hook (2011)

SOLO verbs are easy to align learning targets with an achievement standard


SOLO can also be used codified for student self-assessment, linking student cognitive level to the task requirement.


source: Hook (2011)

The above are few sample of many, on how SOLO can be easily adopted by teacher and students. IT creates a common school language and framework for instruction, learning, and assessment.

Pam Hook writes a succinct Critique of Bloom’s Taxonomy and details advantages of SOLO model over Bloom’s :

    Advantages of the SOLO model for evaluation of student learning
    • There are several advantages of the SOLO model over the Bloom taxonomy in the evaluation of student learning.
    • These advantages concern not only item construction and scoring, but incorporate features of the process of evaluation that pay attention to how students learn, and how teachers devise instructional procedures to help students use progressively more complex cognitive processes.
    • Unlike the Bloom taxonomy, which tends to be used more by teachers than by students, the SOLO can be taught to students such that they can learn to write progressively more difficult answers or prompts.
    • There is a closer parallel to how teachers teach and how students learn.
    • Both teachers and students often progress from more surface to deeper constructs and this is mirrored in the four levels of the SOLO taxonomy.
    • There is no necessary progression in the manner of teaching or learning in the Bloom taxonomy.
    • The levels can be interpreted relative to the proficiency of the students. Six year old students can be taught to derive general principles and suggest hypotheses, though obviously to a different level of abstraction and detail than their older peers. Using the SOLO method, it is relatively easy to construct items to assess such abstractions.
    • The SOLO taxonomy not only suggests an item writing methodology, but the same taxonomy can be used to score the items. The marker assesses each response to establish either the number of ideas (one = unistructural; _ two = multistructural), or the degree of interrelatedness (directly related or abstracted to more general principles). This can lead to more dependability of scoring.
    • Unlike the experience of some with the Bloom taxonomy it is relatively easy to identify and categorise the SOLO levels.
    • Similarly, teachers could be encouraged to use the 'plus one' principle when choosing appropriate learning material for students. That is, the teacher can aim to move the student one level higher in the taxonomy by appropriate choice of learning material and instructional sequencing.

Want more? Here is a link on  Problems with Bloom's Taxonomy (Invalid, unreliable, impractical)

Want to dive into SOLO model? Check out Pam Hook’s Website. Start with these two introductory books: