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PSYCHOLOGY: RESEARCH METHODS - Coggle Diagram
PSYCHOLOGY: RESEARCH METHODS
EXPERIMENTAL DESIGN
REPEATED MEASURES
all participants take part in all conditions of the experiment (4 sets of data)
EVALUATION
ORDER EFFECTS ARE A PROBLEM: Participants may do better or worse when doing a similar task twice, reducing the validity of the results.
PARTICIPANTS MAY GUESS AIMS: Participants may change their behaviour, which may reduce the validity of the results.
PARTICIPANT VARIABLES: The person in both conditions has the same characteristics. This controls an important CV.
FEWER PARTICIPANTS: Half the number of participants is needed than in independent groups, so less time spent recruiting participants.
MATCHED PAIRS
pairs of participants are matched on a variable that may affect the DV then one member of each pair is assigned to a different condition (2 sets of data)
EVALUATION
MATCHING IS NOT PERFECT: Matching is time-consuming and cannot control all relevant variables, and so may not address participant variables.
MORE PARTICIPANTS: Twice as many participants are needed than in repeated groups for the same data, and so more time is spent recruiting, which is expensive.
PARTICIPANT VARIABLES: Participants are matched on a variable that is relevant to the experiment, which enhances the validity of the results.
NO ORDER EFFECTS: Participants are only tested once, and so there are no practice or fatigue effects, enhancing the validity of the results
INDEPENDENT GROUPS
participants are allocated to different groups where each group represents one experimental condition (2 sets of data)
EVALUATION
MORE PARTICIPANTS: Need twice as many participants as repeated measures for same data. More time spent recruiting, which is expensive.
NO ORDER EFFECTS: Participants are only tested once so cannot practise or become bored or tired. This controls an important CV.
PARTICIPANT VARIABLES: The participants in the two groups are different, acting as EV/ CV. This may reduce the validity of the study.
WILL NOT GUESS AIM: Participants are only tested once and so are unlikely to guess the research aims. Therefore behaviour may be more 'natural'.