Research Methods Y1 - Experimental Design Flashcards
What is the definition of experimental design?
The different ways in which the testing of participants can be organised in relation to the experimental conditions.
What is an independent groups design?
Participants are allocated to different groups where each group represents one experimental condition.
What is a repeated measures design?
All participants take part in all conditions of the experiment.
What is a matched pairs design?
Pairs of participants are first matched on some variable(s) that may affect the DV. Then one member of the pair is assigned to Condition A and the other to Condition B.
What is random allocation, and why is it important?
An attempt to control for participant variables in an independent groups design which ensures that each participant has the same chance of being in one condition as any other.
What is counterbalancing, and why is it used?
An attempt to control for the effects of order in a repeated measures design: half the participants experience the conditions in one order, and the other half in the opposite order.
What is the structure of an independent groups design, and what does it involve?
One group of participants (Group 1) experiences one level of the IV (e.g., drinking the energy drink - experimental condition).
A different group of participants (Group 2) experiences a different level of the IV (e.g., drinking water - control condition).
The performance of the two groups is then compared.
How does a repeated measures design reduce variability between participants?
In this design, all participants take part in all conditions of the experiment (e.g., Condition A and Condition B), so differences between individuals are eliminated as a confounding variable.
What are the advantages of using a matched pairs design?
Participants are matched on variables that are relevant to the experiment, such as IQ scores, reducing the impact of participant variables. This ensures more comparable conditions between groups.
What is one evaluation point for independent groups design?
Point: Independent groups designs may lead to participant variables confounding results.
Evidence: Differences between groups may account for variations in the DV rather than the manipulation of the IV.
Explanation: Random allocation reduces this risk by ensuring participants are evenly distributed across conditions. However, randomisation cannot account for all participant variables.
Link: This limitation demonstrates how individual differences can interfere with causality in experimental research, highlighting the need for careful control techniques.
What is one evaluation point for repeated measures design?
Point: Repeated measures designs face the problem of order effects influencing results.
Evidence: For example, participants may perform better in the second condition due to practice or worse due to fatigue (a confounding variable).
Explanation: Counterbalancing can help by varying the order of conditions for participants, but residual effects from earlier conditions can still persist.
Link: Despite this, repeated measures are often preferred due to requiring fewer participants, making them more efficient for small-scale studies.
What is one evaluation point for matched pairs design?
Point: Matched pairs design reduces confounding variables but is resource-intensive.
Evidence: Participants matched on key variables like IQ or age provide more reliable results as participant differences are controlled. However, time and effort required for matching make this approach less feasible for larger studies.
Explanation: Additionally, unmatched variables can still affect results, especially in cases of imperfect matching.
Link: This limitation makes matched pairs less practical in many settings, though it remains ideal for experiments needing high control of participant variables.
What is one evaluation point regarding the sample size and practical concerns?
Independent groups design requires twice as many participants as repeated measures to obtain the same data for each condition, making it less economical and harder to recruit larger samples.
