Designing and Conducting an Extended Investigation (Units 3–4 Coursework)
The investigation as an argument, not a topic
In Units 3 and 4 the extended investigation is assessed on how well a sustained, self-directed inquiry is designed, justified and carried out. The single most important concept is that your research question must be researchable, focused and defensible. A question such as "Is social media bad?" fails because it is evaluative, vague and unanswerable within your resources. A stronger version names a population, a variable and a context: "How does daily Instagram use relate to self-reported sleep quality among Year 11 students at my school?"
Methodology and justification
You must understand the difference between methodology (the overall logic and design of the inquiry) and methods (the specific tools used). Methodology includes your approach (quantitative, qualitative or mixed), sampling strategy, data-collection instruments and analytical framework. Examiners and assessors reward explicit justification: why this method, for this question, given these constraints. You should also understand ethics (informed consent, confidentiality, minimising harm, appropriate storage of data), validity and reliability, and how to manage bias, including your own positionality as a student researcher.
Traps to watch
Common traps include: confusing methodology with methods; proposing a question that is too broad or already answered; ignoring feasibility (time, access, sample size); failing to link each method back to the research question; and treating ethics as a formality rather than an integral design element. Another trap is claiming a causal relationship from correlational data.
Worked rule of thumb
Use the "so what, and how" test: for every design choice, write one sentence explaining what it allows you to find out and why an alternative would be worse. If you cannot, the choice is not yet justified.
Keeping records
Maintain a research journal or log that documents decisions, changes and reflections. This evidence supports both your report and the oral presentation, and demonstrates the iterative nature of genuine inquiry.