Experimental Designs Flashcards
What are the 2 prongs of an experiment?
manipulation and control
What is a weakness of descriptive designs?
Descriptive designs can’t manipulate variables and thus lack control
What is a one group pretest and posttest design?
A single group is tested before or after some treatment. Not an experiment because there is no control
What is a weakness of one groups pretest and posttest designs?
There is no comparison group nor a control, therefore you can’t rule out confounds
What are the 3 conditions to make a causal inference?
Covariation btw IV and DV
Time-order relationship btw IV and DV
Eliminate alternative explanations
Define internal validity?
The extent to which you can make a causal inference based on an experiment
If control is sufficient and all causal requirements are met, then any differences between groups must be caused by the ______.
IV.
What are some threats to internal validity?
A different variable other than IV can affect DV.
Participant reactivity
Experimenter effects
What are some ways to deal with other variables affecting changes to DV?
Assess and control statistically
Randomize!
What is attrition?
loss of participants in a study
Define attrition due to mechanical loss?
Factors that are external to the participant
What is attrition due to selective subject loss?
factors internal to the participant
What are ways to combat attrition?
Pretesting
