Developing a progression model for IBDP biology

Originally posted on November 24, 2018 @ 4:00 pm

I recently completed Daisy Christodolou’s “Making good progress?”. You can see my notes here. In the final chapters, after presenting an argument building up to this, she outlines the key aspects of what she terms a “progression model”. In this post I want to line up some ideas about what this may look like in delivering the IB DP Biology course.

In her book Christodoulou suggests, and I agree, that to effectively help students make progress we have to break down the skills required to be successful in the final assessments into sub-skills and practice these. This is a bit analogous to a football team practicing dribbling, striking or defending in order to make progress in the main game.

In the book she also stresses the difference between formative and summative assessments, what they can and can’t be used for respectively and why one assessment can’t necessarily be used for both.

A progression model for biology

A progression model would clearly map out how to get from the start to the finish of any given course, and make progress in mastering the skills and concepts associated with that domain. In order to do this we need to think carefully about:

1. What are the key skills being assessed in the final summative tasks (don’t forget that language or maths skills might be a large component of this)?
2. What sub-components make up these skills?
3. What tasks can be designed to appropriately formatively assess the development of these sub-skills or, in other words, What does deliberate practice look like in biology?
4. What would be our formative item bank?
5. What could be our standardised assessment bank?
6. What are appropriate summative assessment tasks throughout that would allow us to measure progress throughout the course?
7. What could be our summative item bank?
8. How often should progress to the final summative task be measured i.e. how often should we set summative assessments in an academic year that track progress?

Key skills in biology

This is quite a tricky concept to pin down in biology specifically and in the sciences in general. What skills exactly are kids being assessed on in those final summative IGCSE or IBDP/A Level exams. I haven’t done a thorough literature review here so currently I am not sure what previous work has been in this area.

However,  I would contend that most final written summative exams are assessing students conceptual understanding of the domain. If this is the case then the skill is really, thinking and understanding about and with the material of the domain. Students who have a deeper understanding of the links between concepts are likely to do better.

In addition, those courses with a practical component, like the IBDP group 4 internal assessment are assessing a students understanding of the scientific process. While it may seem like these components are assessing practical skills per se, they only do this indirectly, as it is the actual written report that is assessed and moderated. To do well the student is actually demonstrating an understanding of the process, regardless of where their practical skills are in terms of development.

Indeed if we look at the assessment objectives of IBDP biology we see that this is very much the case. Students are assessed on their ability to: demonstrate knowledge and understanding and apply that understanding of facts, concepts and terminology; methodologies and communication in science etc.

Sub-skills

How can we move students to a place where they can competently demonstrate knowledge and understanding, apply that understanding as well as formulate, analyse and evaluate aspects of the scientific method and communication.

The literature on the psychology of learning would suggest breaking down these skills into their subcomponents. This means we need to look at methods that develop knowledge and understanding from knowledge. Organising our units in ways that help students see the bigger concepts and connections between concepts within the domain will also help. For more on this see my previous post here. I think that understanding develops from knowledge.

I recently read that Thomas Khun claimed that expertise in science was achieved by the studying of exemplars. Scientific experts are experts because they have learned to draw the general concepts of the specific examples.

Useful sub-skills would be:

• Fluency with the terminology of the domain
• Ability to read graphs and data
• Explicit knowledge of very specific examples
• Explicit knowledge of abstract concepts illustrated by the specific examples
• Ability to generate hypothesis and construct controlled experiments

Deliberate practice in biology

Thinking about these sub-skills, then, we can see what may constitute deliberate practice in biology and thus what would make useful formative assessments within the subject.

Fluency with the terminology can be gained through the studying of terminology decks like those available on quizlet. In addition, the work of Isabel Beck. Suggests that learning words isolated from text is not that helpful to gaining an understanding of those terms. To gain this, students need to be exposed to these words in context. Therefore there is a lot to be said for tasks and formative assessments that get students reading. Formative assessments could then consist of vocab tests and reading comprehension exercises of selected texts.

Reading and interpreting data can be improved through practice of these skills. This is an area where inquiry alone won’t help students make progress. Students need to be shown how to interpret data and read tables and graphs before making judgements. Ideally, in my opinion they should do this once they have learned the relevant factual knowledge of a related topic. Formative assessments focussing on data interpretation should therefore come a little later once students have covered a bulk of the content.

To build up conceptual understanding, students need to be exposed to specific examples related to those topics as I outlined in this post. Tests (MCQs) that assess how well students know the specific details of an example could be useful here to guide learners to which parts they know and those they don’t.

Following this we can begin to link examples together to build knowledge of a more abstract concept. Concepts can then be knitted together to develop the domain specific thinking skills: thinking like a biologist.

Formative assessments

Formative assessments could take the form of MCQs but as outlined above, vocab tests, reading comprehension activities, and other tasks may well have their place here.

Summative assessments for measuring progress

I am now thinking that to truly assess student progress against the domain, individual unit tests just won’t cut it. As Christodolou argues, summative tests exists to create shared meaning and do that need to be valid and reliable. Does scoring a 7 in a unit test on one topic of an 11 topic syllabus mean that the student is on track to score a 7? Not necessarily. Not only is the unit test not comparable to the IB 7 because it is only sampling a tiny portion of the full domain, but the construction and administration of the test may not be as rigorous as that of the actual IB papers.

Clearly it isn’t ideal to use the formative assessments described above as these are nothing like the final summative assessment of the course, plus their purpose is to guide teaching and learning, not to measure progress.

I would argue that summative assessments over the two-year course should use entire past papers. These past papers sample the entire domain of the course and performance against them is the best method of progress in the domain. A past paper could be administered right at the start of the course to establish a base line. Subsequent, infrequent, summative tests, also composed of past papers could then measure progress against this baseline.

Why should summative assessments use past papers? What not use unit tests? Unit tests, aggregated, is not the same thing as performance on a single assessment sampling the whole domain. They cannot produce the same shared meaning as an assessment that samples the entire domain. In addition the use of many single unit, high stakes tests will cause teaching to the test as well as much more student anxiety. Instead lots of formative testing and practice of recall should help to build students confidence in themselves.