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What's Our Best Taxonomy? Bloom's or SOLO?

Assessment is one of education's new four-letter words, but it shouldn't be, because it's not assessment's fault that some adults misuse it. Assessment is supposed to guide learning. It creates a dynamic where teachers and students can work together to progress their own understanding of a subject or topic. Assessment should be about authentic growth.

Testing in the U.S. is very different from assessment. I know that sounds absurd but tests have more finality here. When it comes to testing, we have a love affair with multiple choice or true and false. We test whether they know the right answer...or not. Lots of tests are made of hard questions and easy ones. How deeply they know the answer doesn't matter, just as long as they know it. State tests focus less on what students know, and more on what teacher's supposedly taught. 

When it comes to assessing student learning, most educators know about Bloom's Taxonomy. They use it in their practices, and feel as though they have a good handle on how to use it in their instructional practices and assessment of student learning. In our educational conversations we bring up Blooms Taxonomy, and debate whether students have knowledge of a topic, and if they can apply it to their daily life.

Interestingly enough, Bloom himself has been quoted as saying that his handbook is "one of the most widely cited yet least read books in American education". We are guilty of doing that from time to time. Its human nature to tout a philosophy that we may only have surface level knowledge of, which is kind of ironic when we're talking about Bloom's Taxonomy.

For a more in depth understanding of Bloom's, the Center for Teaching at Vanderbilt University website says, "Here are the authors' brief explanations of these main categories from the appendix of Taxonomy of Educational Objectives (Handbook One, pp. 201-207):

  • Knowledge - "involves the recall of specifics and universals, the recall of methods and processes, or the recall of a pattern, structure, or setting."
  • Comprehension - "refers to a type of understanding or apprehension such that the individual knows what is being communicated and can make use of the material or idea being communicated without necessarily relating it to other material or seeing its fullest implications."
  • Application - refers to the "use of abstractions in particular and concrete situations."
  • Analysis - represents the "breakdown of a communication into its constituent elements or parts such that the relative hierarchy of ideas is made clear and/or the relations between ideas expressed are made explicit."
  • Synthesis - involves the "putting together of elements and parts so as to form a whole."
  • Evaluation -  engenders "judgments about the value of material and methods for given purposes."

According to the @LeadingLearner Blog, "it (Bloom's) was revised in 2000. In Bloom's original work the knowledge dimensions consisted of factual, conceptual and procedural knowledge.  Later the metacognitive knowledge dimension was added and the nouns changed to verbs with the last two cognitive processes switched in the order.

  • Remember
  • Understand
  • Apply
  • Analyse
  • Evaluate
  • Create"

The criticism with Bloom's is that it seems to focus on regurgitating information, and that anything goes. A student can provide a surface-level answer to a difficult question, or a deep answer to a surface-level question. It may show a student has an answer, but does it allow for teachers and students to go deeper with their learning, or do they just move on?

According to Pam Hook, "There is no necessary progression in the manner of teaching or learning in the Bloom's taxonomy." If we want students to take control over their own learning, can they use Bloom's Taxonomy, or is there a better method to help them understand where to go next?

Going SOLO

A much less known taxonomy of assessing student learning is SOLO, which was created by John Biggs and Kevin Collis in 1982. According to Biggs, "SOLO, which stands for the Structure of the Observed Learning Outcome, is a means of classifying learning outcomes in terms of their complexity, enabling us to assess students' work in terms of its quality not of how many bits of this and of that they got right."

According to Biggs and Collis (1982), there are five stages of "ascending structural complexity." Those five stages are:

  • Prestructural - incompetence (they miss the point).
  • Unistructural - one relevant aspect
  • Multistructural - several relevant and independent aspects
  • Relational - integrated into a structure
  • Extended Abstract - generalized to new domain

For a better look, here is a diagram provided (with permission) by John Biggs 


If we are going to spend so much time in the learning process, we need to do more than accept that students "get" something at "their level" and move on. Using SOLO taxonomy really presents teachers and students with the opportunity to go deeper into learning whatever topic or subject they are involved in, and assess learning as they travel through that learning experience.

Through reading blogs and research, one of the positives sides to SOLO is that it makes it easier for teachers to identify the levels, and therefore help guide students through the learning process. Ad for my unschooling friends, this has implications for all students, whether they are within the four walls of a school or outside of them.

John Hattie (Peter is a Visible Learning Trainer) is a proponent of SOLO Taxonomy, and has broken it down to an easier way for students to understand which gives them the ability to assess their own learning. Hattie suggests that teachers can use:

  • No Idea - equivalent to the prestructural level.
  • One Idea - equivalent to the unistructural level
  • Many Ideas - equivalent to the multistructural level
  • Relate - equivalent to the relational level
  • Extend - equivalent to the extended abstract

Lastly, Hook goes on to say, "there are some real advantages to SOLO Taxonomy.

  • 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.
  • Both teachers and students often progress from more surface to deeper constructs and this is mirrored in the four levels of the SOLO 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.
  • 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.

Connect with Peter on Twitter.

For other blogs about SOLO see @LeadLearner's Redesigning Classrooms Using Solo to Increase Challenge 

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