M8: Quantitative Research Design - Experimental Designs Flashcards
What is an Experimental Design?
The researcher manipulates the independent variable(s) to determine if it has an effect on the dependent variable(s)
Notation
TORN
What are Pre-experimental Designs?
- Participants receive the intervention/treatment of interest
- Limited control over threats to internal validity
- Participants not randomly assigned to groups
- Changes in the DV cant be attributed to manipulation of IV
What is a One-Shot Study?
One Group receives the treament and then a measurement is taken after some time
Cant actually come to a conclusion becuase no baseline tested
Too many extraneous variables at play
What is a One-Group Pretest-Posttest Study?
- Just 1 Group, no randomization, IV = TIME
- Measure baseline, introduce intervention, measure again
- Try to determine the magnitude of the treatment effect
- Researcher cannot attribute any changes in
performance to the treatment (maturation)
What is a
Posttest Only with Non-equivalent Groups?
- Between-groups design
- Groups are not randomly formed (intact groups)
- Cannot be determined if group A and B are equivalent at the beginning of the study
– Differences between O1 and O2 cannot be attributed to
the treatment
What are True Experimental Designs?
Random assignment
Assumes personal factors that could influence participants
scores on the DV are distributed evenly across groups (groups are equivalent), thus changes in the DV are more likely due to the manipulation of the IV
True Experimental Design
What does Random assignment help control?
Helps control for:
– Past history
– Maturation
– Testing
What does Random assignment
NOT help control for?
Does not control for:
– Measurement errors
– Something happening other than the treatment to one group, but not the other group
– Experimental mortality
What is a
Posttest only Control Group Design?
- Only one group gets treatment
- No baseline test, so nothing to compare with
- Need to add a pre-test
b/w groups
Posttest only Control Group Design
w/ an extra test group
A different intervention added
Posttest only Control Group Design
w/ Two Levels of IV
What is a
Pretest-posttest Control Group Design?
- Mixed factorial design
- Determine how much more change is observed
in Group A vs. Group B - Can be extended to include more observations and independent variables
What is a
Solomon Four-Group Design?
- Combines posttest only and pretest-posttest control
group designs - Determination if there is a testing threat to internal
validity and if the pretest interacts with the treatment - Replication of treatment effect
What is the benefit of doing
Solomon Four-Group Design?
Can observe if the baseline testing affected the outcome -
(Group B - Group D) - (O4 & O6 should be the same)
Can observe if baseline testing affected treament
(Group A - Group C) - (O2 & O5 should be the same)
