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IB Psychology IA Guide: How to Write a Top-Scoring Report
The Psychology IA is the one piece of IB coursework you fully control. Yet most students leave marks on the table. They misread what examiners actually reward.
This IB Psychology IA guide walks you through each section of the report and translates the rubric into plain language. It is built from patterns found in IBO examiner reports and the official Psychology subject guide.
Whether you are an SL or HL student, a parent supporting revision, or a tutor guiding your class, this walkthrough gives you a clear path from topic selection to final draft.
If you want one-on-one support from an IB Psychology tutor, that option is always available alongside this guide.
What Is the IB Psychology IA?
The IB Psychology IA is a student-designed experimental study written as a formal report of 1,800 to 2,200 words. It counts for 25% of the SL grade and 20% for HL. Your teacher marks it first, then the IBO moderates externally.
This is not a survey, a case study, or a correlational analysis. It must be a true experiment. That means you manipulate an independent variable (IV) and measure its effect on a dependent variable (DV).
Students design, run, and write up the study on their own. However, the class may share one common procedure. The final IB Psychology IA report follows the same structure as a published psychology paper.
The four required sections are introduction, exploration, analysis, and evaluation. Each one maps directly to a rubric criterion, which is why understanding the rubric early matters so much.
How Is the IB Psychology IA Rubric Scored?
According to the IBO Psychology subject guide, the IA is marked across four criteria. Each criterion is scored from 0 to 6, giving a total of 24 raw marks. Those marks convert to a criterion level during external moderation.
The table below summarizes what each criterion rewards in plain language.
| Criterion | Mark Range | What the Examiner Looks For |
|---|---|---|
| Introduction | 0 to 6 | Clear rationale linking theory to an operationalized hypothesis |
| Exploration | 0 to 6 | Justified method design with concrete ethical safeguards |
| Analysis | 0 to 6 | Correct descriptive and inferential statistics with clear results |
| Evaluation | 0 to 6 | Design-specific limitations tied to actual validity threats |
The difference between a 3 or 4 and a 5 or 6 comes down to one thing: reasoning. Students who describe their procedure score in the middle. Those who explain why they made each design choice score at the top.
Top-scoring Psychology IA examples share a common trait. Their evaluation section directly addresses threats raised in the exploration. It does not rely on filler statements like "the sample size was too small" without explaining how that affected specific results.
How Do You Choose a Strong IA Topic?
Pick a classic cognitive or social psychology experiment that uses a simple IV and DV design and can be ethically repeated in a school setting. This protects your ethics approval and makes your statistical analysis far easier to handle well.
Run every potential topic through this filter before committing to it.
- Is it a true experiment with a clear, manipulable IV?
- Can the DV be measured with interval or ordinal data?
- Can you run it ethically without complex deception?
- Does a published source study exist for your theoretical framework?
- Is the procedure simple enough to replicate in a classroom?
Some topic categories work especially well. Stroop effect variations (Stroop, 1935) are popular because the IV and DV are clean and measurable. Memory recall studies based on Loftus and Palmer (1974) also give students a strong published framework to build on.
Avoid survey-based topics that measure attitudes with no IV. Qualitative designs do not meet the IA requirements. Overly ambitious neuroscience topics often lack a procedure you can actually replicate in school.
If you are unsure whether your topic works, an experienced IB Psychology tutor can help you pressure-test your idea before you invest weeks of work.
What Should Each Section Include?
Each of the four sections maps to one rubric criterion. Write every section to answer the examiner's implicit question for that criterion, not just to describe what you did.
How Do I Write the Introduction?
Link your background theory to a clear, operationalized hypothesis. The aim should flow logically from the research you cite. It should not appear as a disconnected sentence dropped in at the end.
Cite two to three relevant studies. Quality of connection matters more than quantity. Each study you cite should build toward your specific research question, not just prove you read broadly.
What Goes in the Exploration?
Detail your method precisely enough that another student could replicate it. Then justify each design choice. Explain why you chose independent measures, why you used a specific sampling method, and why you controlled the variables you did.
Address ethics with specifics. Name your informed consent procedure, state the right to withdraw, and describe how you kept data anonymous. Generic ethics statements score poorly.
How Do I Present the Analysis?
Present descriptive statistics first: mean, standard deviation, and an appropriate graph. Then move to inferential statistics. Choose the correct test and state why you chose it.
Most IAs use a Mann-Whitney U test for ordinal or non-normal data, or an independent-samples t-test for interval data with normal distribution. State your result, significance level, and whether the hypothesis is supported.
Save all interpretation for the evaluation section. The analysis should present findings without explaining what they mean.
If you need help choosing the right statistical test, working with an IB Maths tutor can be useful for understanding the logic behind your choice.
What Makes a Strong Evaluation?
This is where the most marks are won or lost. Evaluate strengths and limitations of your specific design, not psychology research in general.
Each limitation must connect back to how it could have affected the DV or your results. IBO examiner reports note that generic weaknesses without a link to a specific validity threat score in the lower markbands for Criterion D.
Suggest modifications that directly fix the limitations you identified. This shows genuine understanding. It separates a thoughtful researcher from a student running through a checklist.
What Mistakes Cost Students the Most Marks?
Three errors cause the most damage across IB Psychology IA reports. Avoiding them puts you ahead of most candidates before you write a word of your evaluation.
- Using a correlational or survey design instead of a true experiment with an IV
- Writing generic limitations that never connect to your actual results
- Exceeding the 2,200 word limit so the evaluation section goes unread
- Placing interpretation in the results section instead of the evaluation
The word count issue deserves extra attention. Examiners stop reading at 2,200 words. Because most students write the evaluation last, going over the limit means your highest-value section gets cut off. Plan your word budget before you start drafting.
Copying rubric language is another quiet mark killer. Repeating the markband descriptors back to the examiner does not demonstrate understanding. Rewrite every point in your own words, tied to your specific study.
Start Writing Your IA With Confidence
The IB Psychology IA rewards methodological clarity and self-aware evaluation far more than topic novelty. Choose a simple, replicable design. Write to the rubric criteria explicitly.
Invest the most time in your evaluation. That is where the strongest students separate from the rest.
If you want structured support from someone who knows the rubric, book a session with an IB Psychology tutor to review your draft or refine your topic.
You can also explore the full range of online tutoring options across IB subjects.
This IB Psychology IA guide is a starting framework. The real gains come from iterating on drafts with informed feedback and keeping your examiner's perspective in mind from the very first sentence.
Frequently asked questions
The IB Psychology IA should be 1,800 to 2,200 words. Appendices, raw data tables, and the title page do not count. Going significantly under suggests the work is underdeveloped. Going over risks the examiner not reading your final sections.
Yes. The task, rubric, and word count are identical for SL and HL students. The only difference is grade weighting. It counts for 25% of the SL final grade and 20% of the HL final grade.
Yes, and examiners often recommend it. A replication with a small modification, such as a different sample or an adjusted variable, is one of the strongest approaches. The theoretical framework is already established, which lets you focus on method and analysis.
It depends on your data type and distribution. Most IAs use a Mann-Whitney U for ordinal or non-normal samples, or an independent-samples t-test for interval data with normal distribution. Justifying your choice is part of the Analysis criterion.
Teachers can provide general guidance and one round of formative feedback on a draft. They cannot edit the report or direct specific changes. The work must be authentically yours, and academic integrity declarations are required by the IBO.
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