Evaluate a Biology Method and Suggest Real Improvements
Biology editorial review is supported by the
named review panel.
Reviewer participation may vary by guide. Checked against Cambridge IGCSE Biology 0610 (2026–2028); last reviewed August 2026.
What this skill means
A complete evaluation links a specific limitation to its effect on the results and then gives a practical improvement. “Human error” and “repeat it” are too vague unless the source and benefit are explained.
Evaluation marks reward cause and effect. The examiner wants to know what could distort the result, why it matters and how the revised method would reduce that problem.
Use limitation → effect → improvement
For example: “Bubble size varies, so counting bubbles does not measure oxygen volume accurately. Collect gas in a gas syringe instead.” Each sentence identifies the weakness, the measurement consequence and a specific improvement.
Choose limitations that fit the method
Look for subjective endpoints, uncontrolled temperature, unequal samples, inaccurate apparatus, too few values, too short a measurement period, contamination or biological variation. Avoid generic phrases that could be copied into any experiment.
Repeats, means and anomalies
Repeats reveal variation and improve reliability. Calculate a mean from concordant values and investigate or repeat anomalous readings. Repeating does not fix a systematic problem such as using an uncalibrated instrument or allowing temperature to drift.
Accuracy and reliability are different
Accuracy concerns closeness to the true value and can improve with more suitable or precise equipment. Reliability concerns consistency and improves with repeats and larger samples. Use the correct term for the improvement being proposed.
Use this before submitting your answer
A complete answer is specific enough for another person to repeat or assess.
✓Name one method-specific limitation.
✓Explain how it affects the measurement or conclusion.
✓Give a feasible improvement that directly addresses it.
✓Separate random variation from systematic error.
✓Use repeats and means only where they solve the identified problem.
Try the skill in a question (4 marks)
A student counts pondweed bubbles to estimate photosynthesis rate. Evaluate this method and suggest two improvements.
Show the answer and marking guidance
Bubbles differ in size, so bubble count is not an accurate measure of oxygen volume.
Collect oxygen with a gas syringe or inverted measuring cylinder instead.
Temperature may rise because of the lamp and independently affect the rate.
Use a water bath or heat shield and monitor temperature.
Original practice content written for this site. It is not an official Cambridge question.