The common pitfalls of biology practical endorsement
03 March 2026
Andri Achilleos, Biology Subject Advisor
This blog was originally published in 2023. It has now been updated to include additional guidance on drawing skills to support centres in strengthening their delivery of the practical endorsement.
The Practical Endorsement (PE) is directly assessed by teachers and is a mandatory part of the A Level Biology A and Biology B qualifications. To pass, candidates need to meet the expectations set out in the Common Practical Assessment Criteria (CPAC). To find out how CPAC is linked to the practical skills you can look through our Practical activities support guide, page 5-8.
Frances Evans, our Principal Monitor, and Steve Savill, Team Lead Monitor, shared their experience from visiting centres. During their visits, our monitors have seen a lot of good practice and excellent implementation of the PE from centres teaching the course.
In this blog I’ll highlight the common issues our monitors encounter during their visits and share their advice on how to overcome these.
Students’ records vs teachers’ records
Sometimes, achievement records do not match the students’ evidence. Teachers should be actively assessing practical competence during the lesson and should use the “Not Achieved” drop-down option in the Practical Activity Groups (PAG) tracker (or by not selecting “Achieved” with the Portable PAG tracker) if needed. There is still the perception of a ‘perfect’ assessed practical, where their learners have to achieve all the skills to ‘pass’ the PAG.
Progression of students’ practical skills as they move through the course is expected. Students’ confidence in PE is usually developed from failure and useful feedback. So constructive feedback can help develop their practical skills in the future.
Recording all practical activity
There is no concept of “PAG and non-PAG practical work” or “assessed practical and not assessed practical work”. The ethos of PE is for students to develop skills in any practical activity, whether it’s large or small. In a couple of cases our monitors noticed that not all practical work done at the centre was recorded in the trackers. All practicals can be used as evidence for completing PE.
Cambridge OCR’s approach to the PE is flexible. Centres can use our suggested PAGs, adapt them, or create their own activities to target specific skills. You don’t need to repeat an entire PAG, you can complete simple activities that target specific practical skills and add them in the PAG tracker.
Giving feedback to students
Sometimes learners are not clear about the specific practical skills they are covering and are therefore not able to track their skill acquisition. A range of tools can be used, but simple skills tick sheets for each PAG are enough. This approach makes it easier to give feedback and ensures consistency in judgements, while helping learners to engage.
Drawing skills
Producing biological drawings sits within 1.2.2(e), Production of scientific drawings from observations with annotations. Students need to be given opportunities to develop this skill with appropriate guidance, as outlined in the biological drawing handbook. Competency in drawing is assessed under the practical skill 1.2.1(f).
The practical skills handbook (page 20), states:
“Some information is best presented by using clear, well labelled diagrams (see Biological Drawing Skills Handbook) or potentially using annotated photographs.”
Experience of correct scientific drawings is usually enough to ‘tick off’ the 1.2.2 (e), Apparatus and technique.
During their visits our monitors have identified issues with the quality of the drawings. Many drawings lack essential features such as annotations and scales, especially when students are working on whole specimens and dissections. Without these features students cannot demonstrate competency in 1.2.1 (f). To achieve competency, students must follow the full drawing guidance.
Tips to support students:
- Students need to familiarise themselves with the guidance for biological drawing before they complete the practical activity.
- Provide candidates with the learner checklist for drawings and encourage them to use it when completing biological drawings.
- If students find drawing challenging while looking at slides under the microscope, you can try and use a whole specimen instead. For example, you can ask candidates to draw a leaf or the kidney, with scale and annotations.
- The guidance for biological drawing is applicable not only for PAG1 and PAG 2, but in all biological drawings that the students will complete during their course.
Strong biological drawing skills don’t just help students during practical work, they also support them in their written exams. The PE is a great chance for learners to build and practise these skills in a supportive, hands on environment.
Tables and graphs
Students should be encouraged to record results straight into appropriate tables for good practice and to avoid transcription errors. Tables are generally very good and where there are errors (such as inconsistent decimal places, units in body of table, calculations in table and no border), in most cases these are picked up by teachers.
One common error with graphs is the lack of headings, and plotting of lines of best fit. According to our practical skills handbook (page 46-47), there must be a reasonable balance of points about the line. A line of best fit can be straight or curved, and they do not have to extend to the origin if this is not appropriate.
Centres are encouraged to use the learner checklist for tables and graphs.
Issues with CPAC 2
CPAC 2, Applies investigative approaches and methods when using instruments and equipment, is usually tackled later in the course by many centres. Although students are evaluating their own method, this is restricted to identifying limitations and improvements. There is usually very little
justification of methodology and selection of variables included. An excellent practice seen in one of our centres was to use two columns for their method. The first column had the steps and the second column was the justification of the steps (i.e. Why?). Our PAGs
1.1,
4.1, and
5.1 have been redesigned to include this.
If learners are struggling to show competence in this skill, our monitors usually advise centres to use PAG 4.3 or PAG 8.3 instead. Students could be asked to plan the experiment, without doing the practical. This can be added as an additional practical activity and could be used to assess only CPAC 2.
Issues with CPAC 5
CPAC 5, Researches, references and reports, also tends to be covered later in the course by centres with little evidence available.
Here are some suggestions from our monitors on assessing those skills beyond PAG12:
- Give the students a topic to research (this can a topic from the specification used as ‘flipped learning’) and then write a report, where they list and cite references.
- Carry out research to create a risk assessment for one of the practical activities, where they list and cite references.
- If the centre offers EPQ, this can provide additional evidence.
- Students plot a graph (such as from one PAG) using computer software (such as Microsoft Excel).
Students should be aware of the correct citation system before they complete the task. Our practical skills handbook (Appendix 7) gives details of the citation system for different resources, as well as suggested websites and books that students can use (Appendix 8). The use of a specific referencing system is not required for the practical endorsement; however, student’s referencing should be complete so that the original source can be identified.
Adjustments and alternative practicals
Here are some alternative activities suggested by our monitors and subject advisor:
- If your students are finding measuring specimens under the microscope challenging (PAG1), you can use the resources available on SAPS for teaching microscopy using plants. The resources include support on how a microscope works, how to prepare specimens for use under the microscope, and how to build students’ confidence in using an eyepiece graticule and how to calibrate a stage micrometer.
- Another useful blog when teaching eyepiece graticules is Teach them big, apply them small by David Goodman.
- This video from SAPS shows how to prepare your own slides to observe mitosis at root tips.
- Use SAPS practical for osmosis with red pepper rather than potato, for shorter lessons.
- If you are using PAG 8.1, try using a chipper to cut the potato rather than core borers. Sometimes core borers are limited in numbers within centres and can be challenging to use. It saves time and avoids wasting resources.
- The PAG 10.1 (student sheet and teacher sheet) has now been updated on Teach Cambridge and includes an alternative version using the online platform Mol*.
- CLEAPSS ‘Make it guide – colorimeter’ offers instructions for producing a simple colorimeter using Lego.
Thank you to Frances Evans and Steve Savill, for sharing their experiences with me.
Stay connected
If you have any questions, you can email us at science@ocr.org.uk or call us on 01223 553998. You can also sign up to subject updates to keep up-to-date with the latest news, information and resources.
About the author
Andri Achilleos was a teacher for ten years before joining Cambridge OCR in January 2019 as the subject advisor for A Level Biology. She studied Biology at University of Bristol and completed an MA in Science Education at University of York. She has taught in Birmingham as Teacher in charge of Biology, as well as an international school in Europe. During her teaching career she has taken on various roles within the department and has also been an examiner for different exam boards.
Related blogs