Experimental designs

• experimental design

  the way in which we use pp's in experimental research
• 3 types of experimental designs

  independent groups, matched pairs, repeated measures
• repeated measures

  - same pp's used for all conditions
• strengths of repeated measures (2)

  - eliminates pp variables

  - more economical
• weaknesses of repeated measures design (2)

  - order effects

  - increase demand characeristics
• independent groups

  - separate and different pp's used in each condition
• strengths of independent groups (2)

  - reduce order effects

  - reduce demand characteristics
• weaknesses of independent groups (2)

  - introduces pp variables

  - less economical
• matched pairs

  - different pp's used in each condition but pp's matched on variables deemed relevant to experiment (age, IQ etc)
• strengths of matched pairs (3)

  - no order effects

  - reduce demand characteristics

  - eliminates pp variables
• weaknesses of matched pairs (2)

  - practically difficult to complete

  - time consuming

  - costly