Manipulated IV in a natural setting
A field experiment has two features and a mark-scheme answer needs both: the researcher manipulates the IV and measures the DV (this makes it an experiment, not an observation or correlation), but does so in a natural, everyday setting — a school, office, street or shop — not a controlled laboratory. Naming the setting alone ('done in a natural environment') is not enough: it drops the manipulation that makes it an experiment.
Field vs natural: who controls the IV
Field and natural experiments both happen outside the laboratory, so they are often confused. The difference is who controls the IV. In a field experiment the researcher manipulates it — say, switching a road sign on and off. In a natural experiment the IV is naturally occurring and cannot be manipulated; the researcher uses one that already exists, like day- versus night-shift workers. Test: did the researcher change the IV, or did it already exist?
Features, strengths and weaknesses paired
Learn the features, strengths and weaknesses as matched pairs. High ecological validity costs weak control of extraneous variables (lower internal validity). Participants are often unaware, so demand characteristics fall — but consent and deception become ethical problems. The IV is still manipulated, so cause and effect can be inferred, yet real conditions cannot be reproduced, so it is hard to replicate. Realism bought at the cost of control.
Drawn from real examiner reports.
Setting-only definition is a tautology
On the 12-mark methods essay, AO1 is the persistent weakness. The classic failure is to write 'it is carried out in a natural environment' and stop. That restates the name (a tautology) and drops the feature that makes it an experiment — the researcher manipulates the IV and measures the DV. For higher AO1, name the IV, DV, controls and setting.
June 2023 P2 Q5
Not a natural experiment or an observation
A field experiment is confused with two methods. Not a natural experiment: it changes the IV, whereas a natural experiment uses one that already exists and cannot be changed, so two pre-existing groups is natural, not field. Not an observation: a field experiment has a manipulated IV and measured DV; an observation only watches, changing nothing.
June 2022 P2 Q5
Don't drift into the study's content
When the 12-mark essay is set on a field experiment, it asks about the method, not the topic the study investigated. A common error is drifting into the content — say, television and eating disorders — instead of the method; that earns no marks. Use the study as evidence about the method: classify it, then evaluate setting, control, validity and ethics.
June 2022 P2 Q5
AO3: named but not linked scores little
AO3 marks are lost predictably: a concept is named but not linked. 'There are ethical issues' earns little — it never says which issue, why, or how it bears on the method. Creditworthy AO3 names one issue (lack of consent), says why the field setting causes it, and judges it. Also AO3 needs AO2: an unlinked evaluation scores nothing.
June 2023 P2 Q5; Q31
Field vs laboratory: setting, not IV
A field and a laboratory experiment both manipulate the IV — the difference is the setting. A field experiment runs in a natural, everyday place (a real shop or street); a lab in a controlled, artificial one with tighter control of extraneous variables. The error is to think manipulating an IV means a lab. Manipulation is shared; setting decides.
'Field' means the real world, not outdoors
The word 'field' misleads students into picturing a literal field or the countryside. In research methods, the field means the real world — any everyday setting where behaviour happens: a school, office, shop or street. It need not be outdoors; what matters is that it is natural, not a lab, with the IV manipulated there. A shop switching its music counts, indoors too.
It has less control, not none
Because it gives up a lab's tight control, students assume a field experiment has no control at all. In fact it is still an experiment: the researcher manipulates the IV and applies some controls (the same task each time). What it cannot control is extraneous variables — weather, noise, bystanders. So: less control than a lab, not none.
Top band on the 12-mark Evaluate
The 12-mark 'Evaluate' has three objectives. AO1: name the manipulated IV, DV, controls and setting, not just the setting. AO2: apply the study throughout. AO3: several balanced lenses (validity, extraneous variables, ethics), then conclude. Do AO2 before AO3.
AO2: use the study's own detail
AO2 means using the study's own detail, not a name or the stem. Weak: 'a field experiment, so realistic.' Strong: 'the café changed its music unannounced, so customers acted normally — high ecological validity.' Tie each point to a real feature, not a pre-learned line.
Match the command word
Match the command word. 'Describe the difference' (field vs natural) needs two definitions plus a connective like 'whereas' — two alone score one mark. 'Explain a strength' means feature + why + consequence. 'State a feature' wants only the point.
Field experiment — an experiment in which the researcher manipulates the independent variable (IV) and measures the dependent variable (DV), but carries it out in a natural, everyday setting rather than a controlled laboratory.
Ecological validity — how far the findings can be generalised to real, everyday situations. It tends to be higher in a real setting.
Extraneous variable — any variable, other than the IV, that could affect the DV. In a real setting these are hard to control.
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