Every IB subject grades its Internal Assessment against a specific set of published criteria, and understanding exactly what each criterion rewards is the single most effective way to raise your score — because it tells you precisely where your effort should go. Below is a breakdown of the criteria structure for the subjects with the highest-volume IAs, so you can see exactly what examiners are checking for.
Group 4 Sciences (Biology, Chemistry, Physics) — Out of 24 marks
- Personal Engagement (2 marks): does the investigation show genuine independent thinking, curiosity, or a personal connection to the topic?
- Exploration (6 marks): is the research question focused and testable? Is the methodology appropriate, detailed, and controlled?
- Analysis (6 marks): is the data processed correctly, with appropriate uncertainty and statistical treatment?
- Evaluation (6 marks): does the student critically assess the validity of their method and conclusion, with specific, realistic improvements?
- Communication (4 marks): is the report clear, logically structured, and appropriately concise?
Where students lose the most marks: Analysis and Evaluation combined make up 12 of the 24 marks, yet these are consistently the weakest sections in average-scoring IAs, because students focus their effort on the write-up of the method instead of the depth of statistical treatment and critique.
Mathematics (AA and AI) — Out of 20 marks
- Presentation (2 marks): is the exploration well-organized, coherent, and appropriately structured?
- Mathematical Communication (4 marks): is mathematical language, notation, and terminology used appropriately and consistently?
- Personal Engagement (3 marks): does the exploration reflect genuine independent thinking rather than a reproduced textbook example?
- Reflection (3 marks): does the student critically reflect on what they’ve learned, the significance of their findings, and the limitations of their approach?
- Use of Mathematics (8 marks): is the mathematics used relevant, correct, and demonstrating an appropriate level of sophistication for the student’s level (SL or HL)?
Where students lose the most marks: «Use of Mathematics» is worth 8 of the 20 marks — the largest single criterion — yet many students choose topics that don’t allow for mathematics beyond the standard syllabus level, capping this criterion regardless of how well-written the rest of the exploration is.
Economics — Out of 45 marks (across three commentaries, roughly 15 each)
Each commentary is typically assessed against criteria covering:
- Diagrams: correct, relevant, and properly labeled
- Terminology: accurate use of economic vocabulary
- Application: how well the theory is linked to the specific facts of the article
- Analysis: the depth and logic of the economic reasoning
- Evaluation: a genuine, reasoned economic judgment
Where students lose the most marks: Application and Evaluation are consistently the weakest areas, because students often explain the theory correctly but fail to tie it explicitly back to the specific numbers and context of their chosen article.
English A (Individual Oral) — Out of 40 marks (weighted to 20% of the final grade)
- Knowledge and Understanding: of the works and the global issue
- Analysis of the works: how effectively literary/stylistic features are analyzed in relation to the global issue
- Focus, Organization and Language: clarity, structure, and register of the spoken presentation
Where students lose the most marks: Weak comparative linking between the two extracts, and plot summary in place of technical analysis.
Psychology — Out of 24 marks
- Introduction: background theory, aim and hypotheses
- Exploration: design, sampling, procedure, and ethical considerations
- Analysis: appropriate statistical treatment and results presentation
- Evaluation: discussion of validity, generalizability, and connection to the original study
- Communication and Presentation: clarity and structure of the report
How to Use These Criteria Strategically
Before writing a single word, print or open the actual official criteria descriptors for your subject (available in your subject guide) and highlight the specific language used for a top mark band versus a middle mark band. Write directly toward that language — if the top band requires «detailed and appropriate,» make sure your report explicitly demonstrates both qualities, not just one.