IB Biology IA Format & Structure (2025)
Everything you need to include to structure your Biology IA the right way.
What is the IB Biology IA Format?
The IB Biology IA is a 3,000-word scientific investigation that counts for 20% of your final grade. You choose the topic, run the experiment, and write up your results in a formal report.
A clear structure helps you stay focused, meet all four criteria, and avoid losing marks for missing or disorganized sections.
Under the 2025 syllabus, SL and HL students follow the same format, with identical expectations for layout, clarity, and presentation.
This guide walks you through each section - so you know exactly what to include, and how to present it the way examiners expect.
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IB Biology IA Report Format: Quick Reference
Before diving into the structure itself, here are the core formatting rules every IB Biology IA needs to follow:
Word limit: 3,000 words (Excludes graphs, tables, equations, citations, and appendices)
Submission format: Typed and exported as a PDF
Font: Arial or Times New Roman, size 11–12
Line spacing: 1.15–1.5
Citation style: Any consistent academic format (APA recommended)
Following these basics keeps your IA clean, readable, and within IB guidelines - all things examiners notice and appreciate.
Suggested IB Biology IA Structure
Use the following section order format to keep your Biology IA organized and easy to mark:
Title Page
Table of Contents (optional but recommended)
Introduction
Research Question
Hypothesis (optional)
Background
Variables
Materials & Equipment
Method
Data Collection & Processing
Data Analysis
Conclusion
Evaluation
References
Appendices (optional)
Use clear section headings - it makes your IA easier to read and mark.
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Title Page
Your IB Biology IA title page should be simple, clean, and easy to read.
Include:
A clear, descriptive title that reflects your investigation
Your full name and IB candidate number
The session or year (e.g. May 2025)
The word count (excluding tables, figures, equations, citations, and appendices)
The priority here is just aligning and spacing things neatly.
Table of Contents (Optional but Recommended)
Including a table of contents isn’t required, but it helps.
Auto-generate it in Word or Google Docs
Makes it easier for examiners to navigate your report
Shows care and organization
If your IB Biology IA is longer or contains multiple graphs, it’s a smart addition.
Introduction
Your IB Biology IA introduction should set up the investigation in a clear and focused way — just enough context to show why the topic matters and how it connects to biology.
What to include:
Brief background and scientific context
Relevance of the investigation - personal or real-world
Key biological concepts or terms the examiner needs to understand
A smooth lead-in to your research question
Save any deep theory or explanation for later sections. The goal here is to orient the reader and show that your topic is grounded in biology.
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Research Question
Your IB Bio IA research question should be specific, focused, and testable through your experiment.
What to aim for:
A measurable relationship between variables
Clear enough that your method directly addresses it
Narrow enough to be explored in the space of one investigation
Common phrasing templates:
How does [independent variable] affect [dependent variable] in [system/condition]?
What is the relationship between [X] and [Y] under [controlled conditions]?
Your RQ is one of the first things examiners look for — make sure it’s clear and easy to find.
Background (Optional)
Include a short background section if your experiment relies on theory that needs context. This is where you can show that your design is rooted in real biology.
Focus on summarizing only the concepts and sources that support your hypothesis, variables, or method. Avoid overexplaining — and skip anything that isn’t directly relevant.
Variables
This section should clearly define your independent, dependent, and controlled variables.
Use a simple list or table format. For each variable:
State what it is
Justify your range or measurement method
Explain how you’ll keep controlled variables consistent
Make sure each variable connects directly to your research question and method.
Materials & Equipment
List everything you used to run your IB Biology IA experiment — clearly and precisely.
Include:
Quantities and concentrations (if applicable)
Uncertainty or precision values for measuring tools (e.g. ±0.01 g)
A labeled diagram or photo, if it helps clarify the setup
Keep the list practical. It should be enough for someone else to replicate what you did.
Method (Procedure)
Your IB Biology IA method should be a clear, step-by-step description of what you did — written in the past tense, using third person.
Include how each variable was measured or controlled
Mention timing, repeats, or conditions that affect accuracy
Optional: Add a setup diagram to support your description
The method section of your Bio IA should make your experiment replicable without needing to guess what you meant.
Data Collection & Processing
This is where you present your raw data in your IB Bio IA — clearly and completely.
Use well-formatted tables with units and uncertainty values
Keep significant figures consistent
Include at least one sample calculation for how you processed your data
If you have large datasets, refer to them in the appendix
No interpretation yet — just the facts, clean and organized.
Data Analysis
Here’s where you process and interpret your data.
Create graphs with titles, labeled axes, error bars, and trendlines if relevant
Point out trends, patterns, and any anomalies
Reference uncertainties where needed
Link your findings to relevant biological theory
The best analyses show not just what happened — but why it matters.
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Conclusion
Your IB Biology IA conclusion should give a direct, evidence-based answer to your research question.
Support your response with key data or averages
Compare results to your hypothesis and relevant theory
Mention any limitations or sources of uncertainty that affect your confidence in the outcome
Keep it focused and rooted in the data, avoiding personal interpretation.
Evaluation
The IB Biology IA evaluation section is your chance to show critical thinking about your work - and how you’d improve it. Aim for balance and insight, rather than simply listing problems.
Identify at least one strength and one weakness in your investigation
Discuss relevant systematic and random errors
Suggest realistic improvements that match the issues you observed
(Optional): Add an extension idea that builds on your results or opens a new question
References and Appendices:
Your references in your Bio IA should follow a consistent academic style — APA is commonly used, but any recognized format is fine as long as you stick to it.
Include full citations for any sources you referenced in your background, theory, or methodology
Make sure your in-text citations match your reference list exactly
Appendices are optional and should only include supporting material:
Raw data tables that are too long for the main body
Full calculation sets
Risk assessments or calibration records
Extra graphs or setup photos
Label each appendix clearly (e.g. Appendix A) and refer to it in the main text if needed. Avoid placing any essential analysis or results here — examiners aren’t required to read it.
Final Tips & Common Mistakes to Avoid in Your Bio IA
A strong Biology IA depends on clear structure, accurate data, and clean presentation — as well as avoiding the common errors that can cost marks.
Common mistakes to watch for in your IB Biology IA:
Inconsistent formatting or unclear structure
Missing units or uncertainty values in data tables
Analysis included in the method section
Important results placed only in the appendix
Using vague phrases like “human error” without explanation
To keep your Bio IA clear and examiner-friendly:
Follow a consistent, labeled structure
Be precise and concise — every section should have a purpose
Use proper headings and spacing to organize your ideas
Treat your IA like a scientific report — objective, readable, and well supported
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