IB Biology IA Marking Criteria – How To Use It For A Top Score

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IB Biology Internal Assessment
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As an IB Biology student, you should know that your final grade isn’t just based on the final exam. A full 20% comes from your Internal Assessment (IA). Naturally, you want it to be a success, and this is why you need to know your Biology IA Marking Criteria.

Have you heard people say “if you don’t know where you are going, how do you know if you get there?”  Well, if you have, it also applies to your Biology IA.  Student needs to provide what the examiners are looking to have a chance of getting the highest grades.

We are here to help you with that. At TutorsPlus, we’ve put together a comprehensive guide on IB Biology Internal assessment marking criteria, to help you get a top score.

Biology IA Marking Criteria Overview

Let’s start with the basics. Your IA is marked out of 24 points, spread across the following five criteria specified by the IB:

  1. Personal Engagement (2 marks)
  2. Exploration (6 marks)
  3. Analysis (6 marks)
  4. Evaluation (6 marks)
  5. Communication (4 marks)

Biology IA Marking Criteria Breakdown

Below, we’ll break the Internal Assessment Criteria down one by one.

Personal Engagement

The first step is making your IA meaningful and relevant for you personally. An experiment without personal significance or relevance to your own life or interests will be marked down. For instance, a good tactic is to choose a research question connected to issues in your local community or region. Think about issues that matter to you or your family and friends.

Furthermore, you need to aim for an original spin – don’t just copy and paste an experiment from a list of Biology IA topics. Customise it! Coming up with your own unique experiment and research question shows initiative, passion, and creative thinking. Brainstorm ideas that grab your attention, find one that gets you excited, and dig in to find the answer. That’s an easy 2 marks right there.


This criterion checks that you’ve set up the scientific background and context properly. You’ll need a descriptive title that captures the essence of your experiment, along with a clear and focused research question. You need to define all your variables – independent, dependent, and controlled, as well as specify the exact units of measurement you will use.

Provide some background about what motivated you to choose this topic – an observation, experience, or story from your life that sparked your interest is ideal. State your hypothesis too, and take care to explain how it is grounded in existing research. You are required to cite at least 5 relevant sources to back up the rationale for your hypothesis.

For many students, one of the most difficult parts is to explain their experiment methodology. You can start with an image or diagram of your full experimental apparatus and list all equipment and materials used, with exact amounts, sizes, models, etc. Then, write out each step of your procedure like you’re giving instructions to another student to replicate your experiment.

Additionally, be sure to note how you controlled variables and made systematic manipulations to isolate your independent and dependent variables. You should conduct at least 5 repeats of your experiment, carefully describing any errors, discrepancies, or difficulties you encountered in the process. Your examiner will be looking for a scientifically rigorous procedure.


This criterion deals with data collection, procession, and visualisation. In this section, you need to introduce the quantitative and qualitative data you collected during experimentation and clearly explain how it helps answer your original research question. Show your work – all calculations must be mathematically accurate and presented in an organised manner. Don’t forget to include a sample calculation in order to walk an evaluator through your method of data processing step-by-step.

Visual representations are vital in Biology IAs. Include properly labelled graphs, charts, and tables displaying relations between variables. There must be informative titles, axis labels with units, legend if needed, and maximum/minimum values. Also, make sure to visually convey any uncertainties, errors, or anomalies in your data where relevant.


This crucial section is where you interpret and reflect on your findings. To begin with, refer back to your original hypothesis – did your results align with or contradict it? Speculate thoughtfully on potential reasons why your hypothesis was supported or disproved based on scientific principles. Identify limitations, sources of error, and weaknesses in your experimental design and methodology – what could be improved or controlled better if you were to convey another experiment? Discuss other confounding factors that may have influenced your data.

Finally, you need to suggest modifications to improve your methodology or experimentation. Evaluators want to see your ability to think critically.

IB Biology Student Researching IA


This final criterion assesses the overall quality of your writing and presentation. Be sure to avoid spelling/grammar mistakes, break up text into clear sections with descriptive headers, properly cite references in the text, as well as fully label any tables/graphs/images.

On top of that, your reference list should include at least 5 relevant sources in alphabetical order, consistently formatted according to the citation style specified by your school. And don’t forget – your IA report should be 6-12 pages long including figures but excluding references/appendices. You’ll lose marks if it’s shorter or longer.

Biology IA Marking Criteria – If You Need Extra Help To Nail Your IA

There you have it – our comprehensive breakdown of IB Biology Internal assessment criteria for a top score!

Also, don’t forget to check out our detailed guide on how to write Biology IA, to know more about its design and format.

Needless to say, it is a lot of work to design, conduct, and write up your experiment. Don’t be afraid to get help along the way. Working with an experienced IB Biology tutor is a great way to refine your skills and take your IA to the next level.

A tutor can provide tailored guidance on developing an innovative research question, perfecting your methodology, analysing data effectively, and crafting a logically structured, scientifically accurate paper. At TutorsPlus, we have a team of talented tutors who have supported many students in achieving top Biology Internal Assessment scores. Feel free to contact us – 41 022 731 8148 or info@tutorsplus.com – if you need that extra boost of expert guidance and mentoring for your Biology IA success.

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