experimental design

• What is independent groups?

  Different groups in each condition.
• How is independent groups done?

  Random allocation to Condition A or B.
• What does random allocation control?

  Individual differences
• What is repeated measures?

  Same group in each condition.
• How is repeated measures done?

  All participants will complete Condition A and Condition B.
• What control measure should be used in repeated measures?

  Counter balancing
• What is counterbalancing?


  Half the participants take part in condition A and then B. The other half do condition B and then A
• What does counter balancing control?

  Order effects
• Counterbalancing .................. order effects.


  Controls for
• What is matched pairs?

  Different groups, matched on participant variable.
• What is the first thing to do in a matcher pairs design?

  A participant variable relevant to the experiment is decided.
• What happens once a participant variable is decided?

  Participants will be tested on this variable.
• What happens once participants are tested on this variable?

  Participants will be paired with someone who is similar on this variable.
• What happens once participants are paired with someone who is similar on this variable?

  One person from each pair will do Condition A and the other Condition B.
• What does independent groups eliminate?

  Order effects
• What are order effects?

  The effect of doing a task twice
• Provide an example of order effects

  Getting bored or better with practice.
• How does independent groups eliminate order effects?

  Participants only complete one condition
• Why is eliminating order effects a strength?

  We know that differences are due to the independent variable, not order effects, improving the validity.
• What does independent groups reduce?

  Demand characteristics
• How does independent groups reduce demand characteristics?

  Participants only experience each condition once, meaning they are less likely to guess the aim
• Why is reducing demand characteristics? a strength?

  We know that differences are due to the independent variable, not demand characteristics, improving the validity.
• What does independent groups have that may affect the results?

  Participant variables
• Provide an example of participant variables

  Differences in age, sex or social background
• Why are participant variables a problem?

  Psychologists can't be certain that the IV caused the changes measured, reducing the validity of the results
• What does repeated measures eliminate?

  Participant variables
• How does repeated measures eliminate participant variables?

  As both of the groups are the same people, there are no differences in participant characteristics
• Why is eliminating participant variables a strength?

  We know that differences are due to the independent variable, not participant variables, improving the validity.
• What may occur in a repeated measures design?

  Order effects
• How are order effects present in a repeated measures design?

  Participants are completing the study twice and therefore they may get bored or better with practice
• Why are order effects a problem?

  We don't know that differences are due to the independent variable, not order effects, decreasing the validity
• Why is matched pairs more advantageous than both independent groups and repeated measures?

  It both eliminates order effects and reduces the impact of participant variables
• How does matched pairs eliminates order effects?

  Participants only conduct the study once
• How does matched pairs reduce the impact of participant variables?

  Each participant is matched on an important characteristic to one in the other condition
• Therefore, it could be argued that the results from matched pairs are what?

  The most valid
• Why challenge is faces with matched pairs?

  It can be extremely difficult to find suitable participants
• Why can it be extremely difficult to find suitable participants?

  If participants cannot be appropriately matched to another, this means that the researcher may need to find more participants
• Why is it a problem that it is difficult to find suitable participants?

  This makes matched pairs an extremely time consuming and more expensive experimental design