Experimental designs in lab + field

Three types

Matched pairs

Independent groups

repeated measures

What are matched pairs

Participants matched for a particular participant variable (each into control and experimental group)

What are independent groups

Participant ms not matched for any participant variables - random allocation

What are repeated measures

Same participants take part in all experimental conditions

Matched pairs evaluation

Matching some participant variables means controlling these variables

High internal validity

Time consuming

Can’t match for every participant variable

Repeated measures evaluation

Participants more likely to respond to demand characteristics

Order effects - order of conditions influences results

Fixed by counterbalancing - different participants do different order