experimental design

Question 1

What is an experimental design?

Answer 1

The way in which participants are allocated to conditions

Question 2

What are the three ways in which participants can be allocated/ put into conditions?

Answer 2

Independent group design
Repeated measures group
Matched pairs design

Question 3

What is the independent group design?

Answer 3

Random allocation to conditions to try and ensure a range of people end up in each group

Question 4

What are the advantages of independent groups?

Answer 4

No order effects (practise effects or fatigue effects)
Less chance of demand characteristics as they only take part in one condition so validity isn’t negatively affected

Question 5

What are the disadvantages of independent groups?

Answer 5

You need more participants as each participant is only used once, but research money is very limited
Individual differences so the groups may differ this becomes a confounding variable which could affect the DV

Question 6

What is the repeated measures design?

Answer 6

When the same participants are used in all conditions useful to see the before and after

Question 7

What are the advantages of repeated measures?

Answer 7

No individual differences as the same person is used so their scores can be compared
Fewer participants needed

Question 8

What are the disadvantages of repeated measures?

Answer 8

Order effects (practise effects and fatigue effects) but this can be balanced out through counterbalancing (half do one half first the others do the other half first)
Some participants may not return for the second condition

Question 9

What is the matched pairs design?

Answer 9

Different, but similar participants are used in each of the conditions. Participants are matched across the groups on any characteristic judged to be important for that particular study

Question 10

What are the advantages of matched pairs?

Answer 10

No order effects as they only take part in one condition
Problems of individual differences are reduced

Question 11

What are the disadvantages of matched pairs?

Answer 11

Matching is difficult and there is often not enough participants to match each person exactly with another
Twice as many participants are needed than for repeated measures so research is more costly