QCE Chemistry IA3 research investigation: how to get top marks

Your IA3 is worth 20% and is marked out of 20, five marks each across four criteria: Forming and Finding, Analysing, Interpreting and Evaluating. You do not run an experiment. You evaluate a claim relevant to Unit 4 using secondary evidence you research yourself, and the marks reward how well you compare that evidence against your specific research question, not how many sources you list.

This guide describes the Chemistry 2025 syllabus (v1.0), which applies to Year 12 students from 2026. Advice mentioning a Communication criterion, or criteria called Research and planning, Analysis and interpretation, or Conclusion and evaluation, was written for the superseded 2019 syllabus and those names no longer exist.

What the task actually asks

You evaluate a claim relevant to Unit 4, chosen from a list your teacher provides. The claim will touch on Properties and structure of organic materials or Chemical synthesis and design, and your job is to turn it into a research question you can actually answer with evidence, then reach a justified position on whether that evidence supports it.

Conditions. Individually written, group-eligible for three research steps (see below), around 10 hours of class time, response up to 2000 words written or up to 11 minutes multimodal. All six syllabus objectives are assessed, unlike the external exam, which examines only four.

What can be done as a group under the 2025 syllabus: selecting the claim, identifying the relevant scientific concepts, and conducting the research. Under the 2019 syllabus students worked individually throughout; this is a genuine change. Everything after research, the analysis and the write-up, stays yours alone.

IA3 swaps IA2's experiment for research: instead of collecting primary data, you gather secondary evidence to evaluate a claim your teacher selects. You are not testing a hypothesis of your own design. The organic materials and chemical synthesis and design topic pages cover the Unit 4 content your claim will draw on.

How it's marked: the four criteria

Communication is not its own criterion under the 2025 syllabus. Referencing and scientific language are marked inside Forming and Finding; genre conventions are marked inside Evaluating.

IA2 splits Forming and Finding into two separate criteria and combines Interpreting and Evaluating into one; IA3 does the reverse, combining Forming and Finding and marking Interpreting and Evaluating separately. If you learned the IA2 structure first, the instinct it gives you here points the wrong way.

What counts as a credible source

The syllabus is more permissive than most students assume. Credible sources include:

• scientific journals
• books and podcasts by well-credentialed scientists
• "popular" science websites or magazines
• websites of governments, universities, independent research bodies or manufacturers

Podcasts and popular science sources are 2025 additions. QCAA's own framing is that the wider list is there "to direct students to a wider variety of student-accessible sources".

Choosing and refining your claim

QCAA's own advice on claim design is that a claim should cue a single Unit 4 context, avoid and/or options, and stay inside Chemistry. It should not drift into biological, economic or ethical territory. Claims it has printed as strong include "Synthetic polymers are chemically superior" and "Molecular manufacturing has revolutionised chemical synthesis". A claim it flagged as weak, "Rusting metal parts dumped in rivers are harmful to the environment", overlaps other sciences and sits outside Unit 4 content.

Your school sets the list you choose from, so the real skill is turning a broad claim into a specific research question. QCAA reproduced one student's own working in its 2025 report: their first attempt, "How does the composition of different pesticides affect volatility, absorption, and solubility", was discarded as "too broad, lacking chemical direction and tried to link unrelated variables". The version they submitted instead was "How do structural differences between the halogenated pesticide DDT and the organophosphorus pesticide malathion affect their chemical stability and environmental persistence?"

Model research questions QCAA has published, usable as templates for the level of specificity expected:

• "Can synthetic silk replace natural silk fibres when considering strength, flexibility and extensibility?"
• "Does the improved synthesis from ibuprofen's original route to its new green route result in less waste reactants and more useful products?"
• "How do structural differences between the halogenated pesticide DDT and the organophosphorus pesticide malathion affect their chemical stability and environmental persistence?"

Each one names the specific substances, the variable being compared and the property in question. None of them just states a topic.

Where strong responses separate from weak ones

Four consecutive subject reports name the same pattern.

Conclusions address the research question, not the claim. The 2025 report's sharpest wording: justified conclusions "discussed how the trends, patterns and relationships identified in the analysis of evidence directly addressed the research question rather than the claim". The claim is handled separately, in Evaluating, by extrapolation.

Quality of evidence means the evidence, not the source's credentials. The 2025 report puts it this way: "insightful discussions about the quality of the evidence addressed the identified limitations and their impact on the ability to address the research question, rather than the credibility of the sources used as evidence". Naming that a source is a journal article is not, by itself, a discussion of evidence quality.

Limitations must say why the evidence is weaker for this question. The top-scoring approach "thoroughly identified how or why each limitation made the evidence less effective in addressing the research question, e.g. by considering which aspect/s of the research question each piece of evidence addressed".

Evaluating: extrapolation versus application

Evaluating is where the top band asks for something specific: extrapolation of your findings to the claim, not application of them. This wording has not changed since 2019, which makes it the most stable piece of criterion language IA3 has.

Application answers your research question. Extrapolation goes one step further and says what your findings do, and do not, license you to conclude about the broader claim. A response that stops at "the evidence supports my research question" has applied its findings. One that adds where that support runs out against the wider claim has extrapolated them.

Common mistakes

Concluding on the claim instead of the research question. Your conclusion in Interpreting has to address the research question you set. Save the claim for Evaluating, where extrapolation is what connects the two.

Discussing source credentials instead of evidence quality. "It's a government website" is not a discussion of bias, currency, relevance or missing data. Say what those factors do to the weight the evidence should carry.

Writing limitations as a generic list. "This source might be outdated" is not a limitation until you say how that affects the evidence for your specific research question.

Offering an improvement or an extension, not both. See the and/or trap above. It costs a paragraph to fix and it is invisible until you read the Evaluating descriptor closely.

Assuming only journal articles are credible. See the credible sources list above. Ruling out government, university and well-credentialed popular sources narrows your evidence base for no reason the syllabus requires.

Treating the research phase as fully collaborative. Selecting the claim, identifying concepts and researching can be shared. Writing near-identical analysis or evaluation with a classmate undermines the individual-work requirement that applies to everything after that.

Choosing a claim that drifts outside Unit 4. If a claim can be answered without touching organic materials or synthesis and design, it is the wrong kind of claim for this task, whatever else is true about it.

Weak versus strong wording

These pairs are drawn from student work QCAA reproduced and annotated in its subject reports, so the right-hand column is what a real top-band response actually did.

Before you submit

• Does your research question name the specific variables involved, not just restate the claim as a topic?
• Does your conclusion address the research question, saving the claim itself for Evaluating?
• Have you discussed evidence quality in terms of bias, currency, relevance and missing data, not just the source's credentials?
• Does every limitation explain how or why it makes the evidence less effective for your specific research question?
• Have you offered both an improvement and an extension, not just one?
• Have you selected sufficient and relevant sources, in a range wider than journal articles only, if that range genuinely serves your question?
• Is your referencing consistent throughout, with a complete bibliography?

See the IA2 student experiment guide for how the criteria regroup when you are working with primary data instead, or head back to the QCE Chemistry study guide for how IA3 fits into the rest of your result.