IB Biology IA Tips

The internal assessment (IA) for IB Biology is a scientific report exploring a research question written by the student. It is worth 20% of the final grade for both SL and HL, and is marked out of 24. Below are tips for each of the five criteria.

Important: Visit the official IBO Biology page for the most updated information about this subject.

Personal Engagement [2 marks, 8%]

A rationale developed in the exploration is good and supports the justification. The danger is personal engagement can be presented as a separate section which is a waste of time and space and is irrelevant.

Many candidates write this as a separate section, but it really does not need to be. It is marked on the essay as a whole, not based upon an invented story. It is better to use this valuable space to focus on the report. Personal engagement may be reflected in your rationale or how you designed the experiment.

Exploration [6 marks, 25%]

A good method can be followed from start to finish simply and result in similar outcomes to those you obtained. Make sure you also plan to collect qualitative data as well as quantitative.

Setting out a clear and well-thought-through research question is vital for the entire report. State the research question (RQ) early and justify why it is suitable.

Use plenty of sources in writing your background information and refer back to them later when supporting any conclusions. These sources can be textbooks, journals, websites, interviews etc. Ensure they are properly referenced using a consistent referencing system.

Always avoid the word amount. It is a vague word with little place in scientific writing. Be more specific — use words such as volume or mass instead.

Think about your method like a recipe. It should be easy to follow: numbered steps, all values for measurements and pieces of equipment clearly stated. Make sure you also plan to collect qualitative data as well as quantitative. There must be consideration of safety, ethical, and environmental issues — all three must be shown to have been explored.

Analysis [6 marks, 25%]

If you are not proficient in drawing graphs with Excel or other software, it may be better to hand draw them on graph paper. Common errors include gridlines being too widely spaced, missing axis labels or uncertainties, and inappropriate lines to represent trends.

If you are doing calculations, you need not show all of them. One example is sufficient. Calculations done using Excel need not be shown in full, but state that they were done in Excel and provide the formula.

Evaluation [6 marks, 25%]

In this section further research should be used to support the explanations given behind conclusions and explore the hypothesis.

Ensure you refer back to your research question and hypothesis in the conclusion. You cannot accept a hypothesis — you can only support or reject it. Data from other scientific experiments or published theory around the topic will support findings well.

In concluding, also mention any qualitative data you obtained and how it supports your overall conclusions. This is often overlooked.

Do not forget to include strengths in your evaluation — they are clearly stated in the criteria and must be addressed. It is generally a good point to say that the number of repeats could have been increased to improve reliability.

Communication [4 marks, 17%]

You may find it more suitable to write conclusions after the evaluation, having considered what the major areas of weakness were and how this may affect the conclusion.

Communication is assessed holistically on the report as a whole. The criteria can be fulfilled by following a clear structure that covers the areas set out by the IA criteria. Learn how to subscript and superscript in your word processor — symbols such as O₂ and Cu²⁺ must be properly formatted. Consistency in decimal places across all results is important.

Final Tip

The guidance is 6–12 pages, not including appendices. Do not put all tables in an appendix — they risk being excluded from marking. Be concise, including only information relevant to your research question. Use a font size of 11 as a suitable, readable size.