🔬The Ultimate IB Science IA Guide

Welcome to your comprehensive guide for acing your International Baccalaureate (IB) Science Internal Assessment (IA)! Use our IB Credit Transfer Tool to see how your grades translate to university credit.

IB Science IA: Quick Guide

Your essential roadmap to acing the Internal Assessment!

The Basics

What is it?

Mandatory! It's an individual investigation.

Weight & Length

20% of your final IB grade. Report: 6-12 pages (conciseness is critical!).

The Goal

To explore ideas and demonstrate skills, not necessarily write a groundbreaking research paper (don't be a perfectionist.)

Time Commitment

Approx. 10 hours class time/teacher meetings + 10 hours individual work. (~20 hours total focused work).

Approach

Hands-on, databases, modelling, simulation, or hybrid.

Assessment

Internally assessed by teacher, externally moderated by IB.

Finding Your Focus

Choose a topic that genuinely interests you! This makes the process more engaging. Think specific, not overly broad.
Example: "Effect of ethanol % on hand sanitizer efficacy" vs. "Climate Change".

Ensure you can collect sufficient quantitative data. Your teacher can help guide you, or provide stimuli.

Assessment Criteria (Max 24 Points)

Important Note

Max score is 24 (SL & HL). Scores are whole numbers (rounded down if needed). Each criterion is marked separately.

A: Personal Engagement

2 Points (8%)

Show genuine interest & independent thinking throughout.

Do: Let your curiosity shine naturally.Avoid: Forcing it or confining it to the intro.

B: Exploration

6 Points (25%)

Focused topic, RQ, background, methodology, safety/ethics.

Do: Be specific, clear, and thorough. Min. 3 replicates if lab work.Avoid: Vague RQs, poor citations (Wikipedia!), ignoring data limits.

C: Analysis

6 Points (25%)

Sufficient raw data (qual & quant), correct processing & interpretation, consider uncertainties.

Do: Process data to answer RQ. Interpret correctly.Avoid: Obvious scientific errors, insufficient data.

D: Evaluation

6 Points (25%)

Detailed conclusion, literature comparison, strengths/weaknesses, errors, improvements & extensions.

Do: Discuss limitations & suggest realistic improvements.Avoid: Superficial suggestions, ignoring errors, weak literature links.

E: Communication

4 Points (17%)

Well-written, logical, clear, concise. Correct terminology, units, sig figs, graph/table labels.

Do: Be precise and professional in presentation.Avoid: Inconsistent sig figs, vague language, imprecise terms.

Comprehensive Information below

The sections below provide a detailed breakdown of each assessment criterion and common pitfalls. Review them carefully!

The Science Internal Assessment (IA) is mandatory for anyone who is taking chemistry/physics/biology Standard Level (SL) or Higher Level (HL), meaning that the students will not receive a grade for the whole subject if they do not complete it.

This rubric and guidance can be used as a help for IB Chemistry IA, IB Physics IA, IB Biology IA.

The Internal Assessment accounts for 20% of your final grade and it is assessed through a single individual investigation. This investigation may involve a hands-on approach, or it may use databases, modelling, simulation, or a hybrid approach. Each student’s work is internally assessed by the teacher and externally moderated by the IB. The official guide states that the report should be 6 to 12 pages long. The students will not get any penalty, however, for submitting an extended investigation as long as they satisfy the rubric and are concise.

Science students in SL and HL undertake a common core syllabus and a common Internal Assessment scheme.

It should be noted that the IA’s goal is to explore ideas, not to write a formal, groundbreaking research paper! It is recommended that students spend around 10 hours of class time and one-on-one teacher meetings, plus about 10 hours working individually on the project. In our experience, it usually takes approximately 20 hours of focused work to produce the desired results.

IB recommends that students find their own stimuli with the help of the teacher. However, teachers sometimes provide a list of stimuli from which the students can choose which one they relate to.

Each investigation is assessed according to the following five criteria:

Criterion A	Criterion B	Criterion C	Criterion D	Criterion E	Total
Personal Engagement	Exploration	Analysis	Evaluation	Communication	-
2 (8%)	6 (25%)	6 (25%)	6 (25%)	4 (17%)	24 (100%)

The final mark is achieved by adding all the marks together; no fractions or decimals are acceptable, and the score will be rounded down if necessary. All criteria are treated separately, meaning that achieving a high score in one criterion does not guarantee a high score on the others. In both HL and SL, the maximum score that can be attained is 24.

When it comes to the sciences, you should choose a topic that really interests you. Instead of a broad topic that you might have difficulty relating to, such as climate change or chemotherapy, you could investigate the effect of the percentage of ethanol on the efficacy of hand sanitizers. Or maybe, as a tea drinker, you can examine the factors affecting caffeine release in a specific period of time in your teacup. In any event, you need to make sure that you have enough quantitative data to perform an investigation.

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IB IA Criteria Explained In More Detail

Criterion A: Personal Engagement

(+2)

Do not forget that the IB wants to see the student's own investigation, showing analysis, interest, and a great degree of engagement. After all, working on a topic that you are interested in is more fun and engaging, right?

You should not force it!! Your engagement should occur naturally and show itself throughout the investigation.

In other words, it is not for the introduction section only; it can also be evident in the experiments that you do in class.

Criterion B: Exploration

(+6)

This section contains your topic, background information, methodology, and, if experiments are involved, ethical or safety considerations.

The topic and research questions should be clearly defined, fully focused, and relevant. For example, instead of broadly speaking about "an investigation into the boiling and melting points in organic homologous series", it is better to be more specific and indicate that you are researching "factors affecting boiling and melting points in organic homologous series." You can always go back and change your topic, of course, but you should make sure that everything is cohesive in the end.

Research objectives should be stated clearly and include both independent variable(s) and dependent variable(s). Background information should not be a general discussion but rather a targeted one. Students can ask someone (e.g. a tutor or their high achieving HL friend!) to read the introduction that includes most of the background information and see if that individual understands what the investigator is going to do and if it is relevant to the investigation.

All the factors that might affect the investigation should be mentioned. If laboratory work is chosen, then the students should perform a minimum of three replicates. Data collected should also be relevant and sufficient to answer the research question. The method should be clearly understandable by the reader.

All materials and methods should be clearly stated. If the investigation is done in the laboratory, the students should show full awareness of safety and ethical guidelines.

Some of the common mistakes in this section include:

The research objective is wordy and not fully focused. For example Instead of writing "I will compare straight-chain simple alcohols of different lengths and branched simple alcohols", it would be more focused to say, "I will compare straight-chain simple alcohols with up to six carbon atoms and their respective branched 2-alcohols." The first statement implies that the student is comparing all or much longer alcohols rather than just the first six. The second statement is much more specific.
incorrect citations or references in the text; the examiner must be able to see which sources you used.
experimental values taken from Wikipedia!
the reliability and limitations of the data were not considered.

Criterion C: Analysis

(+6)

The investigation should include enough qualitative and quantitative raw data to do a proper investigation and reach a conclusion. If it does not have enough data, the remainder should be collected, preferably with the same method as the original data. The uncertainties should be included and considered in all calculations.

Data processing should be targeted towards answering the research question.

The data should be correctly interpreted. Not being able to interpret your own data is not a good sign.

Some of the common mistakes from real IAs are:

Obvious scientific mistakes (e.g. naming of compounds)
Relevant but insufficient raw data.

Criterion D: Evaluation

(+6)

A detailed conclusion, based on a reasonable and relevant interpretation of the data, must be made. The relevant literature should be used correctly to compare and contrast the data or draw conclusions. Limitations, strengths, and weaknesses of the investigation should be addressed, and the student should show a clear understanding of them. The examiner knows that the student has not spent a lifetime working on this project, so s/he is not expecting a robust scientific work (although it might turn out to be). However, the examiner is expecting the student to be able to discuss and summarize their reasons for arriving at the tentative conclusions. Sources of error should be identified and dealt with thoroughly, and their effect on the investigation should be explained.

"Realistic and relevant suggestions" for the improvement and extension of the investigation should be clearly outlined. Possible modifications that might lead to correcting the errors should be specified. Students should also mention possible future work.

Some of the common mistakes from real IAs are:

the student suggests limited future paths of inquiry but does not state why that approach is relevant and of interest.
the student does not make suggestions for improvement and extension.
the student makes only a superficial connection to the literature.

Criterion E: Communication

(+4)

This section, like personal engagement, is evaluated throughout the report. The report should be well-written and logically presented. The information should be study-specific and not vague or general. Subject-specific terminology and conventions should be correctly used, such the complete and correct labelling of the graphs, tables and images, and the correct use of units and decimal places.

Some of the common mistakes from real IAs are:

Inconsistent significant figures.
vague explanation.
use of imprecise terms like "fat solvent" in the materials and methods section.

Frequently Asked Questions: Mastering the IB Science IA

Logistics & Rules

Is the 12-page limit strict?+

The guide recommends 6-12 pages. While there is no automatic penalty for going over, examiners often penalize long reports under Criterion E (Communication) for lacking conciseness. Aim for quality, not volume.

Does the IA count for 20% in both SL and HL?+

Yes. The weighting (20%) and the assessment criteria (max 24 marks) are identical for both Standard Level and Higher Level students.

Can I do a simulation instead of a hands-on lab?+

Yes. You can use databases, simulations (like PhET), or modelling. However, you must still process the data yourself. You cannot just copy a graph from a website; you must generate your own analysis from the raw data.

How many independent variable increments do I need?+

To establish a valid trend (linear or curved), you generally need at least 5 increments (e.g., temperatures of 20, 30, 40, 50, 60°C). Anything less makes the analysis statistically weak.

Can I work in a group?+

You can collect data in a group if the experiment is complex, but the Research Question, Analysis, and Write-up must be unique to you. If your report looks too similar to your partner's, you risk academic misconduct. This is different from the Extended Essay which must be entirely individual.

What if my experiment doesn't work?+

A failed experiment is not a failed IA. You can score very high marks in Criterion D (Evaluation) by analyzing why it failed (systematic error, limitations of methodology) and suggesting scientific improvements. Don't let exam anxiety get to you!

Do I need a hypothesis?+

Yes, usually in the Introduction. It must be a scientific prediction (e.g., "As temperature increases, rate will increase because kinetic energy increases..."), not just a guess.

Can I use ChatGPT to write my Introduction?+

No. The IB scans for AI content. You can use it to brainstorm topics, but the writing and specific analysis must be yours. AI often fails to provide the specific, localized context required for "Personal Engagement."

Do I need to include raw data?+

Yes. Examiners need to see the raw data (in a table) to verify your processing. If the dataset is massive, put a sample in the body and the rest in an Appendix.

Who grades the IA?+

Your classroom teacher grades it first. Then, the IB selects a random sample of students to be "moderated" (checked) by an external examiner to confirm the teacher's grading standard.

Scoring & Strategy Hacks

How do I fake 'Personal Engagement'?+

You don't fake it; you show it through initiative. Don't just say "I love chemistry." Show engagement by doing a preliminary trial to refine your method, or by modifying a standard school lab to test a unique variable.

What counts as 'Analysis' (Criterion C)?+

Analysis is more than just a graph. It includes Error Propagation (calculating uncertainties) and interpreting the trend. Does the line go through the origin? Is the relationship proportional or exponential? Discuss the math of the chemistry. See our Math IA Guide for more on mathematical analysis.

How do I score full marks in 'Communication' (Criterion E)?+

Be consistent with Significant Figures. Label every graph axis with units and uncertainties (e.g., "Time ±0.01 s"). Ensure the report flows logically and scientific terminology is used precisely (e.g., "mass" vs "weight").

What is the difference between 'Random' and 'Systematic' error?+

Random Error: Unpredictable fluctuations (e.g., reaction time). Reduced by doing more trials.
Systematic Error: A flaw in the apparatus (e.g., a heat loss in calorimetry). Cannot be fixed by more trials; must be fixed by changing the method.

Do I really need 3 replicates (trials)?+

Yes. Without 3 trials, you cannot calculate a Standard Deviation or identify anomalies. A single trial is scientifically invalid and will severely hurt your Analysis score.

How specific does my Research Question need to be?+

Hyper-specific.
Bad: "How does heat affect reaction rate?"
Good: "How does increasing temperature from 20°C to 60°C affect the rate of reaction between 1.0M HCl and Magnesium ribbon?"

Can I use Wikipedia as a source?+

Never. Use it to find keywords, but cite academic textbooks, journals (e.g., ChemGuide, PubChem), or reputable scientific organizations. Citing Wikipedia signals poor research skills.

What is 'Safety and Ethics' (Criterion B)?+

You must explicitly state hazards (e.g., "HCl is corrosive") and disposal methods. If using human subjects (e.g., in Biology), you must provide evidence of consent forms. Ignoring this can cap your Exploration marks.

Should I discuss 'qualitative' data?+

Yes! Observations like "the solution turned blue" or "vigorous bubbling" support your numerical data. It shows you were observant during the lab, which boosts your Personal Engagement score.

Can HYC tutors help me pick a topic?+

Yes. Our expert IB tutors can help you brainstorm a topic that is "safe" (likely to work) but complex enough to score high marks. We can also review your methodology to ensure it is scientifically valid before you start. Check out our tips for IB students.

About the Author

This page was written by Masoud, a Certified Teacher holding a Master of Applied Science in Chemical Engineering and a Master of Science in Environmental Biotechnology.