experimental design

what is an independent groups design

two participant groups experience one condition ach

what is a repeated measures designs

where all participants take part in both conditions

what is a matched pairs design

Participants are matched on a characteristic that is important to the study then they take part in different conditions

define random allocation

An attempt to evenly distribute participant differences across experimental conditions

define counter balancing

An attempt to control for order effects in a repeated measures design: half the participants do the conditions in one order and the other half in the opposite order.

what is an example of order effects

fatigue

what are the strengths of an independent groups design

• Order effects are not a problem.

• Participants are less likely to guess the aims of the study

what are the limitations of an independent groups design

• Participant variables differ between groups, which can act as a confounding variable and reduce validity

• More time and money is spent on recruiting participants

what are the strengths of a repeated measures design

• Participant variables are controlled, leading to higher validity.

• Fewer participants are needed, making it more economical in terms of recruitment.

what are the limitations of a repeated measures design

• Order effects (e.g., practice or fatigue) can occur, which acts as a confounding variable

• Participants are more likely to work out the aim, increasing the potential for demand characteristics

what are the strengths of a matched pairs design

• Order effects are not a problem as participants only take part in one condition.

• Demand characteristics are less of a problem.

• There is an attempt to control for participant variables.

what are the limitations of a matched pairs design

• Participants can never be matched exactly, so participant variables are not fully controlled

• Matching can be time-consuming and expensive