QCE resources

Improvements vs Extensions in QCE Science Assignments

A clear guide to writing better improvements and extensions in QCAA student experiments and research investigations.

Updated 2026-05-13 ยท 2 min read

Improvements vs extensions in QCE Science assignments

Improvements and extensions are not the same thing. Mixing them up can make your evaluation sound generic, even when your data analysis is good.

Improvements fix the current investigation

An improvement should make the same investigation more valid, reliable or accurate.

Good improvements usually come directly from a limitation:

  • If trial data was inconsistent, increase repeats or control the inconsistent condition.
  • If the instrument was not precise enough, use a more precise measurement tool.
  • If the variable range was too narrow, test a wider but still relevant range.
  • If temperature changed during the experiment, control temperature more carefully.
  • If secondary evidence used different conditions, find or generate evidence under matching conditions.

The test is simple: would this change help answer the same research question better? If yes, it is probably an improvement.

Extensions investigate a related new question

An extension moves beyond the current research question while staying connected to the broader claim or topic.

Examples:

  • After testing one concentration range, investigate another range where the relationship may change.
  • After testing one species, material or fuel, compare a related species, material or fuel.
  • After measuring one dependent variable, investigate a related outcome.
  • After evaluating one part of a claim, investigate another factor that the claim depends on.

The test is different: does this create a new but related question? If yes, it is probably an extension.

Weak examples to avoid

Avoid writing:

  • "Do more trials" without saying why more trials are needed.
  • "Use better equipment" without naming the measurement issue.
  • "Research more sources" without explaining what kind of evidence is missing.
  • "Investigate other factors" without naming a specific factor and why it matters.

These sound like filler. Strong evaluation is specific.

A stronger sentence pattern

For improvements:

"Because [specific limitation] affected [validity/reliability/accuracy] by [effect on data], the investigation could be improved by [specific change]. This would strengthen the conclusion by [link to research question]."

For extensions:

"Because this investigation only considered [narrow focus], a useful extension would be to investigate [related new variable/context]. This would test whether the broader claim still holds when [new condition] is considered."

Sources