What is the maximum mark for the IB Physics IA?

The IB Physics Scientific Investigation is marked out of 24, using four criteria of 6 marks each: Research Design (6 marks), Data Analysis (6 marks), Conclusion (6 marks), and Evaluation (6 marks). The IA is worth 20% of the total IB Physics grade at both SL and HL.

What do IB Physics IA examiners look for in Research Design?

In the Research Design criterion, examiners look for a clearly stated research question with one independent and one dependent variable, specific background physics that links those variables, a hypothesis grounded in a manipulated equation, a complete variables table (independent, dependent, and all control variables with methods for controlling each), and a method detailed enough for a competent student to replicate without asking questions. The range and number of data points must also be justified.

How should I handle uncertainty in my IB Physics IA?

Uncertainty must be visible in your raw data table, processed data table, and graph. Write instrument uncertainties under the raw data table to one significant figure. Use half the smallest division for analogue instruments and the last displayed digit for digital instruments. Show error bars on both axes where appropriate. Draw a best-fit line and maximum and minimum acceptable lines through the error bars, then use these to calculate the uncertainty in the gradient. The percentage uncertainty in the gradient is then used in the Evaluation criterion to judge the precision of your result.

What makes a high-scoring IB Physics IA Evaluation?

A high-scoring Evaluation identifies at least three specific weaknesses of the investigation (not generic ones), explains why each weakness matters physically and what effect it had on the result or gradient, and proposes a realistic school-laboratory improvement that directly addresses each weakness. It also uses the percentage uncertainty in the gradient to judge precision, and compares the experimental result to a theoretical or published value to judge accuracy. The evaluation must close by linking back to the strength of the conclusion.

How do I get full marks in the IB Physics IA Conclusion?

To get full marks in the Conclusion, report the equation of the best-fit line with units, interpret the physical meaning of both the gradient and the intercept, describe the trend (linear or non-linear, positive or negative), identify any anomalies and explain their likely causes, compare your result to a theoretical or published value and state whether it falls within your uncertainty band, and directly answer your research question. Every claim must be backed by a numerical result from your data.

The 24/24 IB Physics IA Checklist [2026]

Most students finish their IB Physics IA and feel… vague. They think it’s probably fine. They hope the examiner will see what they were going for.

That vagueness costs marks. Sometimes a lot of them.

This checklist is adapted from my book, IB Physics Internal Assessment, published by Zouev Publishing. I’ve been teaching and marking IB Physics IAs since 2004, and this is the checklist I wish every student had before they submitted.

The checklist below removes the vagueness. It is organised exactly the way the IB examiner marks your work: criterion by criterion, point by point. If you can tick every box honestly, you have covered every mark band across all four criteria.

Your aim is simple: leave no marking decision to chance.

Your goal is not to write a perfect investigation. Your goal is to leave no marks on the table that belong to you.

How to use this checklist

Work through it after you have a complete draft. Be honest with yourself. If you cannot tick a box, you have found exactly where marks are slipping. Fix the evidence, not the wording.

The interactive checklist below tracks your progress across all four criteria. Your ticks save automatically so you can come back and pick up where you left off.

Why this checklist works

The IB Physics IA is marked against four criteria of 6 marks each. Examiners are not looking for genius. They are looking for evidence. Evidence of clear thinking, careful measurement, honest analysis, and rigorous evaluation.

Every box in this checklist corresponds to something an examiner is explicitly looking for. Not because I made it up, but because I have been teaching and examining IB Physics since 2004, and I have read enough examiner reports to know exactly where marks fall through the gaps.

The three most common reasons students lose marks are:

1. Variables without enough detail

Most students list their variables. Fewer explain them properly. Your independent variable table should include what it is, its units, the apparatus you used to change it, the range you used, and any practical issues with changing it. If you have just written “distance (cm)” in a box, you have left marks on the table.

2. Graphs that are almost right

The graph is one of the highest-yield parts of the IA, and it is where good students lose surprising numbers of marks. Missing units on axis labels. Error bars that are shown for Y but not X. A best-fit line forced through the origin when the physics does not require it. A maximum and minimum line missing entirely. These are not difficult things to fix. But you have to know to look for them.

Fix visible evidence, not wording. If the examiner cannot see it on the page, it does not exist.

3. Evaluation that describes but does not explain

Students write evaluations that list weaknesses. Examiners want evaluations that explain why each weakness matters physically, what effect it had on the result, and how a specific realistic improvement would address it. “Use better equipment” is not an improvement. “Replace the metre ruler with a digital calliper (resolution ±0.01 mm) to reduce the percentage uncertainty in the length measurement from 3% to 0.2%” is an improvement.

A note on the Final Self-Audit

The four questions at the end of the checklist are the most important ones. They are not marking points, but they are the filter that catches the rest.

If another student could not reproduce your investigation from your method, Criterion 1 is incomplete.

If your uncertainty treatment is buried in a paragraph of prose rather than visible in tables and graphs, Criterion 2 is incomplete.

If any claim in your conclusion is not backed by a number from your data, Criterion 3 is incomplete.

If any improvement you list would not actually improve the data quality in practice, Criterion 4 is incomplete.

Go back and fix the evidence. Not the wording.

If you are still in the early stages of your IA and need help choosing a strong topic, start with my 100 IB Physics IA ideas. If you need the complete structure from start to finish, the IB Physics Scientific Investigation guide walks you through every section.

The GradePod TrIBe course includes a step-by-step IA video course and personalised first-draft feedback from me. If you want me to read your IA before you submit it, that is where to start.

Get the GradePod Exam Pack for £39 →

Sally Weatherly is a Fellow of the Institute of Physics, author of 4 IB Physics books, and founder of GradePod. She has been teaching IB Physics since 2004 and has helped 30,000+ students since 2020.