IB Chemistry IA Criteria Explained:
Your Checklist for Scoring Top Marks on Your Chemistry IA (SL and HL) - Everything you need to know about the IB Chemistry IA criteria - broken down clearly and simply.
Need help with your Chemistry IA? Get expert support on research questions, data analysis, and evaluations — from IB tutors who know exactly what examiners want.
Before we get into the assessment breakdown, here’s what you need to know:
What is the IB Chemistry IA?
It’s a student-designed investigation where you plan and carry out a chemistry experiment. You’ll explore a question of interest, collect and analyze data, and present your findings in a structured report.
How much is it worth?
The IA counts for 20% of your final Chemistry grade (SL and HL). It’s one of the most controllable parts of the course — and a strong IA can make a big difference to your final result.
IB Chemistry IA Criteria: Quick Overview
Your Chemistry IA is graded out of 24 marks, across four criteria — each worth 6 marks. These are the backbone of your report, and hitting each one properly is key to a top score.
Criterion A: Research Design
A clear research question and a well-thought-out method. Define your variables, outline your procedure, and explain why your approach makes sense.Criterion B: Data Analysis
Collect enough data, process it correctly, and show you understand what it means. Include uncertainties, clear tables/graphs, and thoughtful calculations.Criterion C: Conclusion
Use your data to answer the research question. Connect your findings to chemical theory and mention how reliable your results are.Criterion D: Evaluation
Reflect on what worked and what didn’t. Identify limitations and suggest specific, realistic improvements.
Think of these as the four anchors of your IA. If each one is done well, your final grade will reflect it.
IB Chemistry SL vs HL: Does the IA Differ?
Whether you're taking IB Chemistry SL or HL, the Internal Assessment follows the same structure and is marked against the same four criteria.
The difference isn’t in the expectations — it's in the depth and complexity students often bring to their investigations.
HL students may choose research questions that involve more advanced theory, calculations, or chemical systems.
SL students might focus on simpler systems or smaller data sets — but with clear design and strong analysis, they can score just as highly.
What matters most is that your IA is well-designed, clearly presented, and scientifically sound. You won’t lose marks for choosing a simpler topic — but you will if your method, data, or evaluation is weak.
Now let’s get into each IB Chemistry IA criterion in detail:
Not sure if your IA is good enough? We’ll help you identify weak points and polish your Chemistry IA before submission.
IB Chemistry IA Criterion A: Research Design
What does strong research design look like in a Chemistry IA?
This first criterion is all about how clearly and thoughtfully you’ve planned your investigation. It covers your research question, experimental method, and whether your design shows you understand the chemistry behind what you're doing.
Here’s what to focus on:
Clarity of Research Question: Your question should be focused, testable, and clearly linked to chemistry — not vague or too broad.
Logical Methodology: Outline your procedure in a way that someone else could follow exactly. Define your variables, controls, and step-by-step method.
Justified Design Choices: Explain why you chose that method, those concentrations, or that equipment. Show the thinking behind your setup — not just what you did, but why you did it that way.
Controlled Variables: Identify what you’re keeping constant, and explain why it matters for the reliability of your results.
Safety and Ethics: Note any safety precautions, disposal methods, or ethical considerations relevant to your experiment.
Examples:
Good Research Design:
An IA that starts with a clear, focused research question, followed by a logical and replicable method. Variables are clearly defined, and the choices behind each step are briefly explained. Safety is addressed.Weak Research Design:
A vague or overly broad question, unclear procedure, missing or unexplained controls, or a method that skips key steps. No justification for the experiment setup or measurement choices.
When this section is strong, the examiner can easily tell you know what you’re doing — and why it matters scientifically.
One step away from top marks? Book a session with an expert who can help you refine your experiment, data, and conclusion - fast.
IB Chemistry IA Criterion B: Data Analysis
How should you handle and communicate data in your Chemistry IA?
This criterion focuses on how well you collect, process, and present your data — and whether your analysis shows a clear understanding of what the numbers actually mean.
Here’s what to focus on:
Relevant and Sufficient Data: Collect enough data points to spot patterns and support your conclusion. Multiple trials and a good variable range are key.
Clarity and Structure: Use well-organized tables and graphs with correct units, labels, and significant figures. Make it easy for the examiner to follow your results.
Uncertainty and Error Treatment: Show measurement uncertainties and apply them through your calculations. Include error bars, and comment on how uncertainties affect your findings.
Correct and Consistent Processing: Calculations must be accurate and consistent. Include sample calculations to demonstrate your method and logic.
Tips for Effective Analysis:
Define everything: If you introduce a formula, explain each variable and why you’re using it.
Use visuals well: Graphs and charts should highlight trends clearly. Label axes, include units, and explain what the graph shows.
Don’t skip steps: Walk the reader through how you got from raw data to results — step by step.
When your data analysis is well-structured and thoughtful, it shows you’re not just recording results — you’re interpreting them like a chemist.
IB Chemistry IA Criterion C: Conclusion
What makes a strong conclusion in your Chemistry IA?
This criterion is about whether you can clearly answer your research question using your data — and show that you understand what your results mean in a chemical context.
Here’s what you need to get right:
Directly Answer the RQ: Don’t waffle — give a clear, evidence-based answer to your research question.
Support with Data: Refer to specific trends, values, and results from your analysis. Your conclusion should match the evidence.
Link to Chemical Theory: Explain your findings using chemistry concepts from the syllabus or literature. Show you understand why you got the results you did.
Acknowledge Uncertainty: Mention how reliable your conclusion is based on uncertainties or variability in the data.
Good vs Weak Conclusions:
Strong: “As the temperature increased, the rate of reaction doubled, consistent with collision theory and literature values. However, due to measurement uncertainty in temperature, exact rate constants may vary by ±0.02 s⁻¹.”
Weak: “The results show a trend. The experiment mostly worked. It proves the hypothesis.” (Too vague. No chemistry. No data reference.)
Think of this as your chance to connect the dots — between your results, your research question, and the chemistry behind it.
Ace your Chemistry IA. Whether you need help designing your method or analyzing your data, our tutors are here to guide you — step by step.
IB Chemistry IA Criterion D: Evaluation
How do you reflect critically on your investigation?
This criterion is about honest, specific reflection — what went well, what didn’t, and how the experiment could be improved. It’s not about being perfect; it’s about showing that you understand your method and its limitations.
Here’s what examiners want to see:
Specific Strengths & Weaknesses: Don’t just say “human error.” Point out actual issues — like inconsistent temperature control or reaction time delays — and explain how they affected your results.
Impact of Limitations: Show that you understand how weaknesses may have influenced your data or conclusions.
Realistic Improvements: Suggest concrete fixes. For example, using a thermostated water bath or automated timing — not just “be more accurate.”
Optional Extensions: You can briefly mention how you’d expand or build on the investigation, if relevant.
What to Avoid:
Generic evaluations (“some errors happened, but I tried my best”)
Improvements with no link to actual problems
Listing flaws without reflection on their impact
The best evaluations are thoughtful and specific. Show the examiner that you learned from the process — that’s what this criterion is really about.
Don’t risk losing easy marks. Use our proven IA checklist to make sure your report hits every assessment criterion, from start to finish.
Need a Hand with Your Chemistry IA? We’re Here to Help.
Stuck on your Chemistry IA? Whether it’s uncertainty calculations, experimental design, or just tying everything together, you don’t have to do it alone.
At Think Smart Tutoring, we offer one-on-one Chemistry IA support to help you move forward with clarity and confidence.
Why students work with us:
Targeted help: Sessions are focused on exactly what you need — whether it’s refining your research question, reviewing your data, or strengthening your evaluation.
IB Chemistry specialists: Our tutors know the curriculum inside out and have helped thousands of students across the globe finish their IAs strong.
If you’re running out of time — or just want an expert to review your work — we’ve got your back.
