Experimental Designs (Pros + Cons)

Question 1

Lab Experiment Strengths

Answer 1

• High control of extraneous variables therefore increasing confidence that there is cause and effect between the IV and DV
• Standardised procedures and instructions are used which enables researchers to repeat the study in the exact same way with other participants
• In a repeated measures design, counterbalancing can be used to reduce design extraneous variables such as order effects

Question 2

Lab Experiment Weaknesses

Answer 2

• Low Ecological validity due to the artificial situation of a lab; the participants may not display behaviour that reflects how they would behave in real life
• Due to having a researcher present, participants may suffer with demand characteristics

Question 3

Field Experiment Strengths

Answer 3

• As participants are in their normal environment, their behaviour is likely to be more valid as it will reflect their true behaviour
• Participants may be unaware they are being studied and therefore less effected by demand characteristics

Question 4

Field Experiments Weaknesses

Answer 4

• Control over extraneous variables is more difficult because the situational extraneous variables are difficult to control, making them less reliable and difficult to replicate in a standardised way
• The researcher cannot be sure that the IV caused the DV due to the lack of control over the environment
• Participants could be unaware that they are being studied which could raise ethical issues

Question 5

Quasi Experiments Strengths

Answer 5

• Due to the IV naturally occurring within the individual it may be more reflective to that individual
• They allow researchers to investigate variables that would be unethical to manipulate

Question 6

Quasi Experiments Weaknesses

Answer 6

• Control over extraneous variables is often difficult; cause and effect is not guaranteed
• They are generally hard to replicate and therefore can lack internal and external reliability

Question 7

Independent Measures Strengths

Answer 7

• Different participants are used in each condition so there are no practice effects
• Participants only see the experimental task once, meaning that they are less likely to guess the aims of the study and change their behaviour as a result`

Question 8

Independent Measures Weaknesses

Answer 8

• Individual differences could act as an extraneous variable and make it look like the IV effected the DV (when it in fact was something about the individual)
• More participants are needed so may be more difficult to find
• Although demand characteristics are reduced in this design, it can be further improved by carrying out a single or double blind test

Question 9

Repeated Measures Strengths

Answer 9

• Individual differences are unlikely to distort the effect of the IV on the DV as participants do both IV levels
• Uses fewer participants, so may be easier to collevt
• If counterbalancing is used, this can reduce order effects

Question 10

Repeated Measures Weaknesses

Answer 10

• Order effects such as practice and fatigue effects do not contribute a valid reflection of their behaviour
• Participants see the experimental task more than once, meaning they are more likely to guess the aim and therefore suffer from demand characteristics

Question 11

Matched Participants Strengths

Answer 11

• Different participants are used in each condition, so there are no order effects
• Participants only see the experimental task once, meaning that they are less likely to guess the aims of the study and therefore reduce demand characteristics
• The effects of individual differences are highly controlled, so less chance of participant extraneous variables

Question 12

Matched Participants Weaknesses

Answer 12

• The similarities between matched participants may be limited; it is difficult to ensure the matching is completely accurate as other variables about the participant may be unknown
• Matching participants can be very time consuming and difficult