Research Methods - Experimental designs Flashcards
Independent groups definition
One group does condition A and a second group does condition B. Participants should be randomly allocated to the experimental group.
Independent group strengths
No order effects - participants do the task once so don’t get better with practise or worse with boredom and fatigue.
Won’t guess the aim - only tested once so behaviour is more natural = higher realism.
Independent group limitations
Participant variables - participants in each group are different so results validity may be reduced.
Less economical - need twice as many participants as repeated measures for the same data and more time is spent recruiting which is expensive.
Repeated measures definition
Same participants take part in all conditions of an experiment. The order of conditions should be counterbalanced to avoid order effects.
Repeated measures strengths
Participants variables - Person in both conditions has the same characteristics.
Fewer participants - half the number needed than in independent groups so less time and money spent on recruitment.
Repeated measures limitations
Order effects are a problem - may do better or worse when doing a similar task twice due to practise or boredom and fatigue.
Participants guess aim - may change behaviour = unnatural, reduces validity of the results.
Matched pairs definition
Two groups of participants are used but they are related to one another by being paired on participant variables that matter for the experiment.
Matched pairs strengths
Participant variables - controlled as participants are matched
No order effects - only tested once so no practice or boredom/fatigue effects.
Matched pairs limitations
Matching is not perfect, is time-consuming and not all relevant participant variables can be controlled.
More participants are needed - twice as much as repeated measures for the same data. Recruitment is time consuming and expensive.
