Experimental Designs

3 Experimental Designs

Repeated Measures

Independent group designs

Matched pair design

Strengths and weakness associated with experimental designs involve these four features?

Order Effects
Demand Characteristics
The Number of participants

Participant Variables

Repeated Measures

the same participants are tested in all conditions

there is no individual differences and use less participants which mean consistent results.

Independent Groups

Different Ps used in each of the conditions, the Ps are randomly allocated to each condition to try and balance any differences.

Matched Pair Design

Similar Participants are used in each conditions, the Ps are matched to another P in other group.

Strengths of repeated measures

No participant variables

Weakness of repeated measures

Order Effects

Demand Characteristics

Strength of Independent group design

No order effects

Less likely for demand charateristics

Weakness of independent

Demand characteristics

Participant Variables

Strength of matched P

Lack of order effects

Less likely for demand characteristics

No participant variables

Weakness of matched p

No of participants

Difficult to do

To prevent practise effects for repeated measures

should use two different equivalent tests

To prevent order effects for repeated measures

Counterbalancing

To avoid Ps guessing the aim of the study - Repeated measures

Present a cover story

Independent Groups: To prevent participant variables

Ps should be randomly allocated to each condition

Matched Pairs: To try and deal with the length of time it takes to match them

Reduce the number of variables you’re trying to match them on