SOLO Taxonomy: An Effective Tool to Measure Students’ Learning Outcomes

Our familiarity with Bloom’s taxonomy may be greater than with Structure of Observed Learning Outcomes (SOLO) taxonomy. Bloom’s taxonomy organises learning objectives hierarchically from basic recall to creation, while SOLO evaluates the depth and structural complexity of student understanding. John Biggs and Kevin Collis (1982) developed it as an educational assessment framework. Teachers use it to classify the quality and complexity of observable learner responses across five SOLO levels, such as pre-structural, uni-structural, multi-structural, relational and extended abstract. Unlike Bloom’s (1956) taxonomy, SOLO focuses on how learners respond. It helps with formative assessment, so teachers can see what to teach next. At the lower levels of SOLO taxonomy, students demonstrate lower-order cognitive skills, while at higher levels students demonstrate the ability to use complex inductive reasoning strategies.
The pre-structural level is the initial stage of SOLO taxonomy, where students demonstrate little or no understanding of a topic and often respond with irrelevant or incorrect information. At this level, students lack meaningful understanding of the subject matter. Their knowledge is often fragmented, superficial, or incorrect, and they are unable to make connections between ideas or apply concepts effectively. Responses at this stage typically miss the point of the task and may include irrelevant comments, factual inaccuracies, or no response at all. Students may rely on rote memorisation without comprehension, which prevents them from engaging with the material in a meaningful way. 
At the uni-structural level, students have one relevant idea. They can define a term, recall a fact, or perform a single step, but they’re still unable to connect it to anything else. They struggle to see the broader implications or relationships between ideas. For example, a student may understand the definition of a scientific term but may not be able to apply it in a practical context or relate it to other concepts within the subject. To support students at this level, teachers can encourage them to explore connections between ideas and provide opportunities for them to practise applying their knowledge in different scenarios. Here teachers can use guided discussions, hands-on activities, and collaborative learning experiences to promote deeper engagement.
At the multi-structural level, students can identify several relevant ideas but haven’t yet connected them into a coherent picture. There is a growing awareness of the complexity of the subject matter. For instance, a student might be able to list the components of a cell and describe their functions but may struggle to explain how these components work together to support the overall function of the cell. To help students progress and develop a more integrated understanding, teachers can encourage them to share insights and challenge each other’s critical thinking through activities such as concept mapping or group projects that require collaboration and discussion.
At the relational level, students begin to connect and integrate different aspects of their knowledge. This is where deeper thinking begins. Students start linking ideas, seeing cause and effect, comparing across contexts. At this level, students belonging to science don’t just know what photosynthesis is; they can explain why it matters for a particular ecosystem and predict what happens when one variable changes.
The highest level of SOLO taxonomy is the extended abstract level. Here, students demonstrate the ability to generalise their knowledge and apply it creatively in novel contexts. Students take their understanding beyond the given context. They generate new ideas, making cross-disciplinary connections, or applying a concept in a way they were not taught. This is harder to plan for, but it is worth building tasks that make it possible.
Bloom’s taxonomy classifies types of cognitive skill, from remembering through to creating. SOLO taxonomy describes the structural complexity of a student’s response to a specific task. Both are useful; but they answer different questions. Bloom’s asks, ‘What kind of thinking?’ SOLO asks, ‘How well-developed is this thinking?’ Bloom’s and SOLO both describe levels of thinking, but they are built differently. Bloom’s is a hierarchy of cognitive skills, such as remembering, understanding, applying, analysing, evaluating, and creating, while SOLO describes the structural complexity of a response. They’re complementary, not interchangeable.
For students, the benefit of SOLO taxonomy is clarity. When they know what a relational response looks like as opposed to a multi-structural one, they have a target. By clearly defining learning objectives and outcomes, SOLO taxonomy helps students understand what is expected of them. This clarity can lead to improved academic performance and a better experience. This nuanced approach helps them move beyond mere recall of facts and figures, instead fostering deeper learning that sticks with them long after the lesson’s over. For instance, when exploring a topic like climate change through SOLO taxonomy, students will not only learn about its causes and effects but also be able to critically evaluate different mitigation strategies and their feasibility. 
Implementing SOLO taxonomy in the classroom can be a transformative experience for teachers. By adopting this framework, educators can rethink their teaching practices and make informed decisions that cater to diverse learning needs. Teachers empowered with SOLO can create more inclusive learning environments where students feel supported and challenged at the same time.
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The writer is President, English Teachers’ Association of Bangladesh (ETAB). He can be reached at [email protected]