Internal Assessment
The scientific investigation — worth 20% of the HL grade — and the full HL assessment outline.
Weighting and basics
- The scientific investigation is worth 20% of the HL grade.
- Marked out of 24.
- 10 hours of allocated time.
- Internally assessed, externally moderated.
- Identical requirements at SL and HL, and identical across biology, chemistry and physics.
Report requirements
The output is a written report of maximum 3,000 words.
Excluded from the word count:
- Charts and diagrams
- Data tables
- Equations, formulas and calculations
- Citations and references
- Bibliography
- Headers
Required at the start of the report:
- Title
- IB candidate code
- Candidate codes of any group members
- Word count
No cover page or contents page is required.
Investigation requirements
You formulate your own unique research question. The investigation must involve collection and analysis of quantitative data, supported by qualitative observations where appropriate.
Permitted approaches (alone or combined):
- Hands-on practical laboratory work
- Fieldwork
- Spreadsheet analysis and modelling
- Extraction and analysis of data from a database
- Use of a simulation
Rules that are easiest to break by accident
- No two students may present the same set of raw data.
- Optional collaborative groups are limited to no more than three. Each student must vary a variable or data subset, and must author their report entirely individually — a group report is not permitted.
- The teacher may read and advise on one draft (advice only — no editing). The next version submitted is final.
- The same work cannot be submitted for both the IA and the Extended Essay.
The four IA criteria
Editorial The exact IA weighting and current criterion names need teacher confirmation (flagged in the research as R-17). These are transcribed from the guide but should be checked against the current assessment guide before relying on them.
Research design
6 marks · 25%
How effectively the student communicates the methodology (purpose and practice) used to address the research question.
Top band: RQ described within a specific and appropriate context; methodological considerations explained; description allows the investigation to be reproduced.
Data analysis
6 marks · 25%
Recording, processing and presenting data relevantly.
Top band: Communication both clear and precise; appropriate consideration of uncertainties; processing appropriate and accurate.
Conclusion
6 marks · 25%
Answering the RQ with regard to the analysis and accepted scientific context.
Top band: Conclusion justified, fully consistent with the analysis (including uncertainties), and justified through relevant comparison to the scientific context (with traceable citations).
Evaluation
6 marks · 25%
Explaining the relative impact of methodological weaknesses and realistic improvements.
Top band: Explains the relative impact of specific methodological weaknesses or limitations, and explains realistic improvements relevant to those weaknesses.
The four criteria are equally weighted at 25% each.
How the mark bands escalate
The 60-hour HL experimental programme
The HL experimental programme totals 60 hours, composed of:
- 40 hours practical work
- 10 hours collaborative sciences project
- 10 hours scientific investigation (the IA)
The collaborative sciences project is not directly assessed in the chemistry grade. It is an interdisciplinary sciences project addressing real-world problems, governed by the separate Collaborative sciences project guide.
HL assessment outline
Editorial This is the HL outline — your assessment structure. SL figures are shown for comparison only and are never your own assessment.
| Component | Duration | Marks | Weighting |
|---|---|---|---|
| External assessment | 4 h 30 min | 165 | 80% |
| Paper 1 (two booklets, completed together without interruption) | 2 h | 75 | 36% |
| Paper 2 | 2 h 30 min | 90 | 44% |
| Internal assessment — scientific investigation | 10 h | 24 | 20% |
Weightings sum to 100% (36% + 44% + 20%).
Paper 1 — two booklets
Paper 1 is taken as two booklets completed together without interruption:
- 1A: 40 multiple-choice questions on SL and HL material, with no negative marking.
- 1B: 35 marks of data-based questions and questions on experimental work.
A calculator and a clean data booklet are permitted in both papers.
Paper 2: short-answer and extended-response questions on SL and HL material.
Editorial — SL for comparison SL Paper 1 is 1 h 30 min, 55 marks (1A = 30 MCQ on SL material only; 1B = 25 marks). SL Paper 2 is 1 h 30 min, 50 marks. These are not your figures — you sit the HL papers above.
Common misconceptions & bridge items for Internal Assessment
Common misconceptions (1)
M-79 — 'Human error' is a valid source of error.
Confidence: verified
Why it’s wrong: It is a non-answer.
Correction: Name the specific measurement, its uncertainty, and whether the effect is random or systematic, and state the direction of the effect on the result.