Biology · Scientific Investigation (IA)
IB Biology Internal Assessment
Upload your Scientific Investigation (IA) and get examiner-level feedback on every criterion — scored against the official IB Diploma sciences internal assessment criteria (scientific investigation, first assessment 2025). Free to try, no account required.
Assessment criteria — 24 marks total
Your Scientific Investigation (IA) is graded against 4 criteria. iBacalao scores each one and tells you exactly where to gain marks.
Research Design
A research question described within a specific and appropriate context: variables (or correlated variables), the system it sits in, and directly relevant background theory. Methodological considerations explained — how variables are measured, scope and quality of the data, control variables, and safety/ethical/environmental issues. Enough procedural detail that the investigation could be reproduced.
Data Analysis
Recording and processing of data communicated both clearly and precisely — correct conventions for tables, graphs, units, decimal places and significant figures — with appropriate consideration of uncertainties, and processing relevant to the research question carried out appropriately and accurately.
Conclusion
A conclusion justified by the analysis — including the interpretation of processed data and its uncertainties — that answers the research question, and is justified through relevant comparison to the accepted scientific context (published values, theory), with traceable citations.
Evaluation
Specific methodological weaknesses and limitations explained — including their relative impact on the results — with realistic improvements that directly address the identified weaknesses.
Common mistakes to avoid
Research Design
Research question stated without context, variables or background theoryMethod missing the detail needed to reproduce the investigationControl variables not identified, or how they were controlled not explainedSafety, ethical or environmental issues ignored
Data Analysis
Tables or graphs missing units, labels or consistent significant figuresUncertainties ignored or treated superficiallyProcessing steps that can't be followed or contain errorsProcessed results that don't address the research question
Conclusion
Conclusion claims more than the data can supportNo comparison with published values or accepted theoryUncertainties ignored when interpreting the resultSources cited too vaguely to be traceable
Evaluation
Generic weaknesses ("human error") not specific to this methodologyImprovements unrelated to the weaknesses identifiedNo discussion of how much each weakness affects the conclusionLimitations of scope or of assumptions not considered
Common questions
How is the IB Biology Scientific Investigation (IA) marked?
Your Scientific Investigation (IA) is marked against 4 criteria totalling 24 marks using the official IB Diploma sciences internal assessment criteria (scientific investigation, first assessment 2025). Your teacher marks first, then the IBO moderates a random sample from your school — so your mark may be adjusted up or down if the moderator consistently disagrees with your teacher.
What is the most important criterion in the IB Biology IA?
All criteria matter, but the highest-weighted criterion — worth the most marks — is "Research Design". Focus on what the mark band descriptor says for the top score and make sure every element it mentions is present in your submission.
Can I use AI to help with my Biology IA?
The IBO allows AI for feedback and research support, but the submitted work must be entirely your own. iBacalao gives criterion-by-criterion feedback on your draft — the same kind of comment your teacher would give — without generating any text for your IA.