Year 9 Science · AC9S9I06

Validity, reproducibility and evidence quality

Judge methods and conclusions separately, locate assumptions, compare conflicting evidence and calibrate claims to uncertainty instead of using “reliable” as a catch-all…

Ready to project and teach

Key conceptTeach from the board

Method evaluation asks whether procedures and measurements can answer the question fairly. Conclusion evaluation asks whether the claim follows from the evidence. A precise dataset can still come from an invalid design; a valid design can still have high uncertainty.

Look for sample bias, uncontrolled variables, measurement limitations, selective reporting and assumptions. When studies conflict, compare method quality, samples, contexts and uncertainty. Scientific conclusions should use calibrated language such as “supports”, “is consistent with” or “does not provide sufficient evidence”, rather than automatic “proves”.

Worked examplesWe do

Worked examples

AC9S9I06 - Validity, reproducibility and evidence quality
Example 1

Identify a validity flaw in a supplied method.

Example 2

Identify what would make the method reproducible.

Example 3

Rewrite “this proves” as a claim proportional to the data.

Example 4

List two reasons two studies might reasonably differ.

Curriculum examplesCopied content

Australian Curriculum v9.0 — AC9S9I06: validity/reproducibility, assumptions, conflicting evidence and uncertainty.

Victoria Levels 9–10 — VC2S10I06:Exact.

NSW Stage 5 — SC5-WS-06 + SC5-DA2-01:Exact/Partial analysis/conclusions and legitimacy of claims together strongly align.

LessonAC v9VictoriaNSW
Method/conclusion evaluationDirectDirectWS-06
Claim legitimacyDirectDirectDA2-01
Questions and answersWith answers
  1. Validity or reproducibility? Validity asks whether the method tests the intended question; reproducibility asks whether others can obtain compatible evidence.
  2. What is an assumption? Something treated as true for the reasoning to work but not directly established by the data.
  3. How should conflicting evidence be handled? Compare quality, context and uncertainty rather than ignoring inconvenient results.
  4. Why state uncertainty? It sets an appropriate strength and scope for the conclusion.
Practice and reviewReady for practice
  • Repeatable means valid. A biased method can repeat consistently.
  • A conclusion should restate the hypothesis. It must respond to actual evidence.
  • Conflicting evidence means choose the study you trust most. Compare methods and uncertainty systematically.
  • Uncertainty makes evidence useless. Uncertainty tells you how strongly to state the conclusion.
Curriculum alignmentStart here
Teach & ExplainTeaching slides and samples

Teach this topic step by step

Explore optional teaching slide packs for classroom lessons and explanations at home.

Browse Teach & Explain · Browse Print & Go

Teachers: follow SkillrHub on TPT, then email us to request a free sample before buying. Include the year, subject and topic or curriculum code.

Request a free sample

After trying the sample, honest feedback is welcome. A TPT review is optional, where available, and does not need to be positive.