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 the 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 ACriterion BCriterion CCriterion DCriterion ETotal
Personal EngagementExplorationAnalysisEvaluationCommunication-
2 (8%)6 (25%)6 (25%)6 (25%)4 (17%)24 (100%)
Criterion APersonal Engagement2 (8%)
Criterion BExploration6 (25%)
Criterion CAnalysis6 (25%)
Criterion DEvaluation6 (25%)
Criterion ECommunication4 (17%)

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.


Criterion A:
            Personal Engagement (+2)

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.


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