Cambridge IGCSE Environmental Management Fieldwork 5: Evidence-based evaluation and management decisions

The final stage of fieldwork is not “the hypothesis was correct”. A strong conclusion answers the aim with evidence and appropriate uncertainty. A strong evaluation explains how the method affected the evidence and proposes improvements that address those effects. Environmental management then adds a further step: deciding what action is justified, for whom and under what constraints.

This Eclat skills note consolidates Cambridge IGCSE Environmental Management 0680 AO3: evaluating methods, identifying limitations, suggesting improvements, explaining patterns, making reasoned judgements and forming evidence-based conclusions.

Forming a conclusion

Return to the exact aim and hypothesis. State the pattern, quote representative values, mention important anomalies and decide whether the evidence supports the hypothesis. Use cautious language where the sample is limited.

For example:

Mean litter abundance was 14 items per quadrat within 20 m of the entrance and 5 items beyond 100 m. Four of five distance bands followed the predicted decline, so the evidence supports an association between greater distance and less litter. The anomalously high count near a picnic shelter suggests that visitor facilities may also influence the pattern.

This is stronger than “the hypothesis was right” because it identifies evidence, pattern and uncertainty. An association does not by itself prove cause. To make a causal claim, consider whether the proposed process is plausible and whether alternative variables were measured or controlled.

Evaluating evidence quality

Use three questions:

• Reliability: Would repeats or independent samples produce a similar pattern? Consider sample size, natural variation and consistency of method.
• Validity: Did the method actually measure the question? A questionnaire about perceived noise does not directly measure sound level, while one pH reading does not represent all aspects of water quality.
• Representativeness: Do the selected sites, times and participants reflect the population or area named in the conclusion?

These properties can differ. A sensor may give precise repeat readings at one unrepresentative location. A large questionnaire may reliably measure the views of visitors but not residents.

Limitation, effect and improvement

An evaluation should form a three-part chain:

1. Name the specific limitation.
2. Explain its likely effect on the results or conclusion.
3. Give a feasible improvement that directly reduces that effect.

Weak: “Human error may have occurred, so repeat the experiment.”

Stronger: “Different observers estimated percentage cover using different visual judgements, increasing variation between transects. Use the same trained observer or a gridded quadrat with a defined counting rule at every site.”