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Module 7: Fact or Fallacy?
Quick questions on Evaluating evidence and claims: HSC Investigating Science Module 7
13short Q&A pairs drawn directly from our worked dot-point answer. For full context and worked exam questions, read the parent dot-point page.
What is the hierarchy of evidence?Show answer
1. Systematic reviews and meta-analyses.
What is what each level rules out?Show answer
A claim about cause and effect requires study designs that can rule out:
What is applying the hierarchy to a media claim?Show answer
When a news headline claims "X causes Y":
What is nHMRC and the Australian context?Show answer
The National Health and Medical Research Council uses the hierarchy of evidence to set Australian clinical guidelines. NHMRC publishes evidence grading:
What is common situations the hierarchy clarifies?Show answer
A new "miracle drug" reported in the news. Usually a Phase II trial or even pre-clinical animal data. Promising but provisional. Treatment in patients requires Phase III RCTs and regulatory approval (TGA in Australia, FDA in the US).
What is when evidence is uncertain?Show answer
Even the highest levels of evidence can be uncertain. RCTs may be too small, too short or conducted on a non-representative population. Meta-analyses depend on the quality of included studies. Honest scientists report uncertainty alongside best estimates.
What is a new "miracle drug" reported in the news?Show answer
Usually a Phase II trial or even pre-clinical animal data. Promising but provisional. Treatment in patients requires Phase III RCTs and regulatory approval (TGA in Australia, FDA in the US).
What is diet and cancer risk claims?Show answer
Usually based on observational cohort studies. Associations are real but confounders are common. Strong dietary recommendations need RCTs (rare for diet because of compliance challenges) or very consistent observational evidence with biological mechanism (e.g.
What is vitamin and supplement claims?Show answer
Industry-funded short trials may show effects. Independent meta-analyses (e.g. of vitamin C and the common cold) often show no clinical benefit.
What is evaluation?Show answer
The claim is supported by Level I evidence with a small but real effect, larger in deficient populations. It is not a "cure" or "prevention" in the strong sense but a measurable reduction in risk in some groups. Stronger evidence supports correcting deficiency than blanket supplementation in well-nourished populations.
What is ignoring effect size?Show answer
A "statistically significant" 1 per cent reduction in risk may not be clinically important.
What is confusing levels of evidence with funding source?Show answer
Industry-funded trials can be high-quality; the level depends on study design and rigour, not who paid.
What is equating expert opinion with evidence?Show answer
Expert opinion is one input; it is not the same as Level I evidence. :::