How do you gather, appraise and use evidence to build a defensible health investigation?
Apply skills of evidence selection and appraisal, judging reliability and validity, to investigate a respectful relationships priority for the IA3 investigation
A QCE Health Unit 4 answer on the IA3 investigation skills of selecting, appraising and using evidence, covering reliability, validity, primary and secondary data, and building a defensible criteria-based conclusion.
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What this dot point is asking
The IA3 is an investigation, and the assessed skill is how well you find, judge and use evidence, not just what you conclude. QCAA wants you to select appropriate data, appraise it for reliability and validity, and use it to build a defensible, criteria-based conclusion about a respectful relationships priority. Many students collect evidence but never weigh it. The strongest responses treat every source critically and let the quality of evidence, not opinion, drive the conclusion.
The answer
What counts as evidence
Health investigations draw on two kinds of evidence:
- Secondary data: existing information from credible bodies such as the Australian Institute of Health and Welfare, the Australian Bureau of Statistics, Queensland Health and peer-reviewed research.
- Primary data: information you gather yourself, such as surveys, interviews or observations of your target group.
Strong investigations triangulate, using more than one source and type so findings are corroborated rather than resting on a single figure.
Appraising reliability
Reliability is about consistency: would the same method produce the same result if repeated? A reliable source uses sound methods, an adequate sample size and a transparent process. A small, self-selected survey or a one-off anecdote is low in reliability. When you cite data, comment on how reliable it is rather than presenting it as fact.
Appraising validity
Validity is about accuracy and relevance: does the evidence actually measure what it claims to, and does it apply to your context? A national statistic may be valid for the country but less valid for a specific local cohort. A leading survey question produces invalid data because it measures the question's bias, not real views. Checking validity means asking whether the source is current, relevant to your population, and free of bias or vested interest.
Using evidence to reach a conclusion
The investigation is judged on analysis and a defensible conclusion. Use your appraised evidence to make a judgement against clear criteria, not a personal preference. Where sources conflict, explain which you trust more and why, referring to reliability and validity. Acknowledge the limitations of your evidence, such as a small sample or an out-of-date figure, because naming limitations honestly demonstrates the critical thinking the top band requires. A conclusion built transparently on weighed evidence is defensible; one asserted over the data is not.
Applying it in the IA3
Plan your investigation around evidence quality. State your inquiry question, choose sources deliberately, and justify why each is reliable and valid for your respectful relationships topic. Where you gather primary data, design instruments that avoid leading questions and reach a representative slice of your group. Then analyse the evidence, weigh conflicting findings, and reach a criteria-based recommendation that you can defend by pointing to the strongest evidence. This evidence-driven discipline is exactly what separates the upper bands from a report of opinions.