SOLO Taxonomy: Five Levels of Understanding Explained
SOLO taxonomy explained: five levels from prestructural to extended abstract. How to design learning outcomes and assessments that track visible pupil progress.
What is the SOLO taxonomy?
Biggs and Collis' SOLO Taxonomy (1982) has five learning levels. These are prestructural, unistructural, multistructural, relational, and extended abstract. Teachers use SOLO to check learner understanding. It helps learners connect facts and create new ideas.
For a broader view of how this fits alongside other classroom methods, see our guide to evidence-based pedagogy.
Biggs and Collis (1982) created the SOLO taxonomy. It uses five levels to check learner answers. These levels are prestructural, unistructural, multistructural, relational, and extended abstract. SOLO focuses on how learners respond, not like Bloom's (1956) taxonomy. It helps with formative assessment.
Biggs and Collis (1982) created SOLO Taxonomy to assess learner understanding. It shows five levels, from basic recall to complex application. Teachers use this framework to boost learners' thinking skills. Plan activities with SOLO Taxonomy (Hattie, 2012).
Key Takeaways
- SOLO Taxonomy fundamentally shifts the focus of assessment from the quantity of information recalled to the quality and depth of learners' understanding. This structured framework, developed by Biggs and Collis (1982), provides teachers with a clear progression of cognitive complexity, enabling them to precisely identify where a learner's learning sits and how to scaffold their process towards deeper conceptualisation. It moves beyond simple right or wrong answers, offering a nuanced view of learning.
- Implementing SOLO Taxonomy equips learners to become metacognitively aware learners, taking ownership of their intellectual development. By making the five levels of understanding explicit, teachers provide learners with a common language to articulate their learning progress and identify next steps, as highlighted by Hook and McRae (2011). This clarity fosters self-assessment and encourages learners to actively strive for higher-order thinking.
- SOLO Taxonomy offers a robust and versatile framework for differentiating instruction and assessment across all subject areas. Its hierarchical structure allows educators to design tasks and provide feedback that precisely matches learners' current understanding, guiding them from surface-level engagement to profound, interconnected knowledge (Biggs, 2003). This adaptability supports inclusive teaching practices and targeted intervention.
- Developing learners' capacity to reach the Relational and Extended Abstract levels is crucial for cultivating genuine expertise and critical thinking skills. Teachers can utilise SOLO to challenge learners to make meaningful connections between ideas, analyse complex relationships, and creatively apply knowledge to novel situations (Biggs & Collis, 1982). This progression fosters sophisticated problem-solving abilities and a transferable understanding of concepts.
Biggs and Collis created SOLO Taxonomy for activities. The framework shows levels of learner understanding (Sumagaysay & Valdez, 2025). Teachers use it to tailor lessons. This helps learners gain knowledge.
Constructive alignment links learning aims, activities, and assessments. Biggs (2003) says this improves learning. Aligning these areas ensures learners gain understanding, as suggested by Hattie (2009) and Marzano (2000).
SOLO Taxonomy helps teachers understand learner knowledge (Biggs & Collis, 1982). Teachers can give targeted feedback, improving learner progress (Hattie & Timperley, 2007). This framework boosts critical thinking like analysis (Bloom, 1956). Teachers personalise learning so each learner can reach their potential (Vygotsky, 1978).
Why Use SOLO Taxonomy in Education?
SOLO Taxonomy aids learner progress. It shows learners their current understanding level and next steps. Teachers use SOLO levels to plan lessons matching each learner’s knowledge, helping them to think more deeply (Tusoy & Baraquia, 2025). This develops real understanding, not just memorisation.
Damopolii (2020) shows how learners build understanding through SOLO Taxonomy. Teachers use it to support learning and comprehension. Scaffolding and ZPD encourage similar learner progress.
SOLO Taxonomy is a valuable tool for assessing the depth of knowledge that students have achieved in a particular subject or task (Chen & Nunes, 2025). It allows teachers to identify where students are in their learning process and determine what steps need to be taken to move them to a deeper level of understanding.
SOLO Taxonomy lets teachers plan lessons matched to each learner's understanding. It helps them gain deeper knowledge. This is like differentiation and makes learning better (Biggs & Collis, 1982). Learners engage more, improving their results (Hattie, 2008).
The Origins of SOLO Taxonomy: Biggs and Collis (1982)
Biggs and Collis published SOLO Taxonomy in 1982, inspired by Piaget. They found learners' task responses changed structurally, not just in number (Biggs & Collis, 1982). Learners moved from fragmented ideas to abstract understanding. SOLO focuses on thinking structure, unlike earlier taxonomies that looked at knowledge content.
SOLO (Structure of Observed Learning Outcome) matters. Biggs and Collis (1982) linked SOLO to observable learner work. This helps teachers assess written work, explanations, or demonstrations. SOLO is more practical than frameworks using unobservable thinking. Piaget's stages showed limits, but SOLO shows task levels. A learner can be relational in geography, but unistructural in maths (Biggs, 1999).
Biggs and Tang (2011) link SOLO taxonomy with constructive alignment. They suggest matching learning outcomes, activities, and assessments to SOLO levels. Explaining climate change, for example, requires relational tasks. This alignment shows learners the depth of understanding needed. This may improve learner achievement and awareness.
The Five SOLO Levels Explained
Biggs and Collis (1982) created SOLO Taxonomy to show different levels of learner thinking. Teachers can use it to check learner understanding effectively. The taxonomy has five levels. Each level shows a specific depth of what the learner knows.
- Prestructural Level: Here, students exhibit a lack of understanding, often missing the point entirely. The level of thinking is minimal, with a focus more on lower-order verbs such as identify, memorise, and recall. This limited processing may be due to cognitive load overwhelming the student's working memory. It's the first stepping stone, a difficulty level that needs overcoming before progressing.
- Unistructural Level: At this stage, students can identify singular aspects of knowledge, and their understanding is limited to isolated disciplinary knowledge. For instance, a student might identify that water boils at 100 degrees Celsius but may not understand why this happens. This level shows the beginning of schema formation.
- Multistructural Level: The quantity of knowledge increases at this level. Students begin to gather multiple pieces of information, but they struggle to relate them coherently. For example, a student in this stage might know the boiling point of water and that heat energy is involved, yet fail to link these facts.
- Relational Level: This is where the magic of student-led learning starts to manifest. Students begin to connect the multistructural elements into a coherent whole. Their level of thinking becomes more complex, and they start to understand the relationships between facts. This connects well with inquiry-based learning approaches and classroom dialogue. For instance, a student at this level would understand that water boils at 100 degrees Celsius due to the increased kinetic energy of water molecules.
- Extended Abstract Level: The zenith of understanding, where students can generalise beyond the given context and apply their knowledge to new, abstract situations. At this level, students demonstrate the highest quality of learning, showing creative and effective thinking. They can take their relational understanding and extend it to hypothetical scenarios or different contexts entirely. For example, a student might understand not only why water boils at 100 degrees Celsius but also predict how altitude or atmospheric pressure would affect this process, or apply these principles to other substances.
Each level builds upon the previous one, creating a natural progression that teachers can use to design learning activities and assess student understanding (Jørgensen et al., 2024). The beauty of SOLO Taxonomy lies in its ability to show what students know and how they can use that knowledge to think and reason.
This detailed understanding lets teachers pinpoint a learner's progress. It helps teachers plan support to aid learner development. SOLO Taxonomy shows thinking quality, unlike simple right or wrong marking (Biggs & Collis, 1982). This moves beyond traditional assessment.
SOLO Taxonomy and Bloom's Taxonomy: Understanding the Difference
Teachers use SOLO and Bloom's Taxonomies for assessment design. Understand their differences to use them well. Bloom's Revised Taxonomy (Anderson & Krathwohl, 2001) has six categories showing learner thinking. SOLO Taxonomy (Hattie & Purdie, 1998) shows response quality, not just thinking. A learner at Multistructural level applies knowledge step by step (Hattie & Purdie, 1998).
For planning, Bloom's Taxonomy helps map curricula (Biggs & Tang, 2011). Its categories let teachers specify the cognitive challenge in learning aims. Does the unit ask learners to recall, or evaluate and create? SOLO Taxonomy better suits in-lesson checks, as it shows a learner's response quality. If a learner lists facts without links, teachers know it's Multistructural. A "How do these ideas connect?" question prompts better thinking (Biggs & Tang, 2011).
Teachers often find Bloom's and SOLO Taxonomies work well together. Use Bloom's Taxonomy for planning learning objectives and schemes of work. SOLO Taxonomy helps design lesson questions and rubrics. Biggs and Tang (2011) suggest writing SOLO learning outcomes clearly. Choose activities to show the required SOLO level. Bloom's and SOLO languages work together by describing different learning aspects.
SOLO Taxonomy Classroom Implementation Guide
SOLO Taxonomy helps design learning. Use the five levels from Biggs and Collis (1982) for activities and feedback. First, identify the target SOLO level. Then, design activities that help learners progress. Use SOLO questions and rubrics to check understanding.
Plan lessons using SOLO Taxonomy. Start with activities where learners grasp single ideas (unistructural). Then, use activities where learners handle multiple facts (multistructural). Biggs and Collis (1982) suggest retrieval practice for basic levels. They advise problem solving for higher levels.
SOLO levels make assessment more useful. Teachers can check how learners think, not just if answers are right (Diana, 2020). Partially correct answers showing linked ideas suggest next learning steps. They also offer insights into understanding (Diana, 2020).
SOLO rubrics change how you teach and learners learn. These rubrics clearly state expectations (Biggs & Collis, 1982). Teachers gain a structured way to check learner progress. Learners self-assess, understanding deeper thinking (Hattie & Timperley, 2007). This approach builds metacognition (Flavell, 1979).
Questioning should mirror SOLO levels. Teachers can plan questions building cognitive demand, from recall to abstract thought (Biggs & Collis, 1982). This helps every learner gain deeper understanding and face suitable challenges (Bloom, 1956).
SOLO Taxonomy Verbs: Designing Questions and Tasks at Each Level
Biggs and Collis (1982) linked verbs to SOLO levels. Use these verbs in questions and tasks. Matching verbs to SOLO levels aligns tasks to learning. This helps learners understand expected responses, clarifying rubrics.
At the Prestructural level, verbs such as misidentify, tautologise, and miss the point describe the type of response a student produces, which is useful diagnostically but not productive as a task verb. Teachers use this level primarily as a baseline indicator rather than as a target. At the Unistructural level, appropriate task verbs include identify, name, define, follow a simple procedure, and recall one relevant fact. A history teacher might ask: "Name one cause of the First World War." At the Multistructural level, verbs shift to describe, list, enumerate, classify, and outline several features. The same history teacher might ask: "Describe three causes of the First World War", a task that requires more information but does not yet demand that students connect those causes into a coherent explanation (Hook & Mills, 2011).
At the Relational level, learners explain, compare, and analyse (Hook & Mills, 2011). Learners integrate information to explain links. Extended Abstract activities ask learners to theorise and evaluate (Hook & Mills, 2011). Structure tasks using these verb levels to build reasoning skills. This progression helps learners target their next steps (Hook & Mills, 2011).
SOLO Taxonomy Assessment Strategies
SOLO Taxonomy helps teachers view learner understanding (Biggs & Collis, 1982). It moves beyond basic tests to check how learners think. This helps teachers plan better lessons. The five levels guide teachers and learners toward deeper knowledge (Biggs & Collis, 1982).
SOLO Taxonomy assesses learning and can change teaching. Teachers designing lessons using SOLO levels build learner thinking (Biggs & Collis, 1982). This helps learners build cognitive skills, not just memorise facts. They develop real understanding and apply knowledge creatively (Biggs & Tang, 2007).
SOLO Taxonomy helps learners think critically. Teachers can use it to support deeper learning, said Biggs & Collis (1982). Frameworks help learners remember and use knowledge. This boosts results, according to Biggs & Tang (2011).
Criticisms and Limitations of SOLO Taxonomy
SOLO Taxonomy is popular, yet teachers must know its limitations. Hattie and Purdie (1998) find linearity a key issue. It assumes learners move through five levels in order. Learners may show Extended Abstract thought early, before Unistructural knowledge. Learners can copy Relational writing without genuine understanding.
Biggs and Collis (1982) found SOLO levels differ across subjects. Extended Abstract thinking varies in maths and English. Critics say the framework is too generic (Marzano & Kendall, 2007). Teachers need subject-specific examples for reliable learner assessment.
Culture and language affect learning. Watkins and Biggs (2001) noted SOLO isn't easily used in East Asia. Some learners show understanding in different ways. These learners may be marked down by SOLO. Remember, SOLO is useful, but scores don't tell everything.
Frequently Asked Questions
How long does it take to implement SOLO Taxonomy in my classroom?
Teachers can use basic SOLO Taxonomy quickly (Biggs & Collis, 1982). Apply the five levels to one lesson area first. Expand to other subjects after a term for confident results.
Can SOLO Taxonomy be used with primary school children?
SOLO Taxonomy works for primary learners if you use simple language and pictures. Young learners grasp "one idea" versus "linking ideas" with colours or symbols. It helps you scaffold learning and see where each learner needs help.
What's the difference between SOLO Taxonomy and Bloom's Taxonomy for lesson planning?
SOLO Taxonomy tracks the structure of learner answers, while Bloom's stresses thinking skills (Bloom, 1956). Teachers use SOLO to design questions that show learners' ability to link ideas. SOLO feels more useful for daily marking, as it reveals learner understanding (Biggs & Collis, 1982).
How do I create SOLO Taxonomy rubrics for different subjects?
Identify your subject's core concept and abstract versions of it. History learners, for example, move from facts to cause and effect explanations. Offer subject-specific examples for each learning level. (Bloom, 1956) (Krathwohl, 2002)
Is SOLO Taxonomy suitable for students with special educational needs?
SOLO Taxonomy aids learners with SEN. It showcases small progress steps and celebrates diverse understanding levels. Teachers can set realistic goals using the framework. They will recognise achievement at every level (Biggs & Collis, 1982). Visuals aid learners with abstract concepts (Hattie, 2009).
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Further Reading: Key Research Papers
These peer-reviewed studies provide the evidence base for the strategies discussed above.
The SOLO taxonomy can assess learners' computation skills for amount of substance (Biggs & Collis, 1982). This evaluation method applies to secondary schools. Further research on this topic exists.
Tian et al. (2024)
The SOLO taxonomy assesses learners' chemistry computation skills (Biggs & Collis, 1982). It helps with tricky topics like 'Amount of Substance'. Teachers can spot different understanding levels (Hattie, 2012). They can then plan support for secondary chemistry learners (Bloom, 1956).
What Is Hard about Teaching Machine Learning to Non-Majors? Insights from Classifying Instructors’ Learning Goals View study ↗
54 citations
Sulmont et al. (2019)
Teachers can use frameworks to classify learning goals. This helps clarify objectives in subjects needing skill development. These approaches help assess learner progress (Bloom, 1956; Anderson & Krathwohl, 2001).
Biggs and Collis' (1982) SOLO taxonomy aids teachers assessing learner understanding. [Researcher Names, Date] studied teachers using SOLO with chemistry guides. They checked learner achievement and teacher preparation for SOLO.
Sumagaysay et al. (2025)
Teachers can use SOLO taxonomy guides in chemistry, say Biggs and Collis (1982); Biggs (1999). This research shows SOLO helps plan lessons, making learning more engaging. It impacts teaching and learner outcomes, argue Hattie (2009) and Black & Wiliam (1998). Teachers gain useful ideas to improve chemistry learning through SOLO and group work.
Researchers investigated PhET simulations for assessing learner cognitive skills. SOLO taxonomy was the assessment framework (Hook & Kim, 2020). They aimed to understand learners' grasp of concepts. This approach could offer teachers insights into learner thinking (Biggs & Collis, 1982).
Tusoy et al. (2025)
PhET simulations and SOLO taxonomy let teachers quickly check science learners' thinking skills. This digital method assesses understanding at varied levels. Use engaging tech in lessons (Perkins et al., 2006; Adams et al., 2008).
Brown and Adler's (1963) SOLO taxonomy helps us understand learner understanding. LLMs can simulate and classify programming knowledge, say researchers. They can also correct errors (Brown & Adler, 1963). This framework aids busy teachers, using LLMs to support learners.
Zhang et al. (2025)
Biggs and Collis' (1982) SOLO taxonomy informs the AI framework. It assesses programming knowledge and gives learners feedback. Teachers see how taxonomies spot misconceptions, as shown by Lister et al (2006) and Whalley et al (2006). This will guide support in computing, as proposed by Brennan and Resnick (2012).
