Bethan Foulkes, Science Subject Advisor

Our Cambridge Advanced National in Human Biology develops applied knowledge, understanding and skills relevant to medical science. In the mandatory Unit F173, Biomedical techniques, students learn about the role of biomedical scientists and the techniques they use.

Many health service departments rely on biomedical scientists to help diagnose conditions and choose treatments. This unit allows students to develop their investigative skills, planning and carry out investigations to assess and analyse biomolecules and biochemicals.

In this blog, I’ll answer some of the questions that teachers often ask and highlight resources Cambridge OCR has to support you.

Why doesn’t the set assignment tell me what the patients are suffering from?

Students don’t need to discover the correct disease for each patient to gain marks. Instead, they are assessed on the methods they choose, how they justify their decisions, and how they interpret their findings. It is up to each student to make reasoned assumptions based on the available evidence and choose the methods that will help prove their assumptions.

Different students may reach different conclusions about a patient’s disease, and this is OK.

Do students need to be able to carry out every biomedical technique in the specification?

You should deliver the entire content of the unit to students, while giving them opportunities to practise the skills needed for the assignment. You should prepare students for the full range of practical skills they can select from when they plan their methods, based on the equipment you have in centre. 

To support you in your delivery of these practicals, we have produced a practical skills booklet. This includes teacher and student sheets, with suggested equipment and methods for the practicals in this unit. You are able to make adaptations to the practicals in this booklet.

Let them know which techniques are inaccessible, but which would be useful in some situations, so that they can justify the choices they make and discuss the limitations and potential improvements in their evaluation. 

For example, electron microscopy is likely to be theoretical in most centre laboratories. However, students should still understand the technique. This will help them with Task 4 when they evaluate their methods and suggest improvements.

How do we make sure students choose the correct practical techniques and tests?

Students need to decide which methods to use based on the patient’s symptoms and the research they have carried out, for all samples. Students should use knowledge and skills they’ve learned in the unit to decide which practicals they would need to use. 

The key requirement is that these methods are feasible with the equipment available in the centre and capable of producing some form of result, not that they guarantee an “expected” outcome.

Do all students need to choose the same practical techniques for the patient samples?

No. Students may choose different techniques depending on the diseases they predict from the samples. At least one practical will need to produce quantitative results so students can access all the criteria for the assignment. As a reminder, students are not informed of the contents of the samples.

How can we support students to plan practical methods that are feasible in our centre?

Before students start planning their investigation, give them a list of equipment and chemicals available in your centre. This will help them plan practical methods that are possible within your centre. 

There’s more information in Amy Brewer’s blog on guidance for an investigative unit. This refers to the Cambridge Advanced National Applied Science, but is relevant to F173 as well.

Is there a required number of practical tests students need to carry out?

Students must carry out at least one quantitative test, on at least one patient sample. This allows students to access the marking criteria for P7: Use standard mathematical techniques to process data. 

Other than this, there isn’t a recommended number of tests for each sample. It depends on the plan students have made, and whether a test provides enough evidence for an answer. 

For example, some students may run initial tests on all samples and then choose follow-up tests depending on the results. 

Time is another important factor. Before students start planning their methods, make sure they know how much time they will have to carry out their investigation.

What if students’ results are anomalous or inconclusive?

There is no penalty for unexpected, anomalous or inconclusive results. In fact, such outcomes often provide a chance for students to demonstrate higher-level evaluative skills for Task 4, which 4 asks them to explain limitations of data, suggest other tests and techniques, assess effectiveness of methods and so on. 

Students can still access the full range of marks by thoroughly evaluating their methods and results, drawing reasoned conclusions, and reflecting on the validity of their findings and how these could be improved. 

The assessment is more about how students investigate the patient samples (within the limits of a school lab), than whether they correctly match each sample with the patient.

Mathematical processing is included in this unit. What do you expect to see here?

The appropriate mathematical skills are identified in Appendix D of the specification. Students don’t need to cover all these maths skills, but these should be your guide to the skills we would expect to see. To achieve P7, students must also show the steps for at least one of the calculations. 

Our mathematics skills handbook gives guidance for all the mathematical skills students should be familiar with for Human Biology. You can also refer to our candidate style work for F173 to see an example of how the criteria related to mathematical processing have been achieved.

When can I give feedback on students’ work, and what feedback is allowed?

You can give feedback once the student’s work has been finished and has been submitted for marking. 

Your feedback can: 

• tell students which criteria they have or have not achieved 
• give general feedback based on the wording of the assessment criteria or guidance 
• point students towards an area or topic of the specification that they have not evidenced well. 

You must not direct or tell students what to do to complete or improve their work. See Section 7.3 of the specification for more detailed guidance. 

The student guide to NEA explains what help and feedback you can give to students. You should share this with students when you start teaching the course, so they understand the requirements for NEA activities.

For Task 1 of the F173 set assignment, students must provide a step-by-step method, a full list of equipment and risk assessment. You should pause and review these before allowing them to continue with the practical task. Your feedback must still be general and cannot explicitly tell students how to improve their work. This stage is a review only, and Task 1 cannot be marked at this point. You can only start marking once the whole assignment is completed.

Can teachers intervene if students get stuck?

Yes. The compensation model allows teachers to intervene when necessary to help students continue with the assignment. You should record details of any support provided and take it into account in assessment decisions.

What resources are there to support me?

All our resources are on our free teacher website, Teach Cambridge. In addition to those already mentioned, there’s a detailed scheme of work for F173, with a variety of suggested activities to choose from to suit the needs of you and your students. 

Our Subject knowledge support sections at the end of topics are very useful for non-specialists and early-career teachers. We have also included a column focusing on Student independent learning. This gives suggestions on ways to flip learning or reinforce concepts, so students can make the most of time outside lessons. 

High on your list before teaching should be the candidate style work, moderators’ reports, and the live set assignments, all available only to teachers through Teach Cambridge. Look out for the common issues students have with accessing command words, expectations around level of detail in responses and how to maximise marks. 

And join us at our professional development events online, especially ‘Ask the Moderator’ and ‘Enhancing your Teaching: Supporting you to deliver investigative skills’. Our teacher networks are also a great way to swap ideas and get support.

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About the author

Bethan joined Cambridge OCR in April 2019 and is a subject advisor for GCSE Sciences and Applied Science. Before that, Bethan taught biology to 11–18 year olds for eight years, and was responsible for planning her school’s biology schemes of learning. In addition to her teaching responsibilities, Bethan mentored PGCE students and NQTs in science, and oversaw all the trainees and NQTs within the school as professional tutor. In her spare time she enjoys dressmaking, quilting and many other different crafts.