Unit 4 Flashcards
What is the literal meaning of ex post facto?
“after the fact”
-> translates to “from a thing done afterward”
What is the purpose of ex post facto research design?
it attempts to determine a cause-and-effect relationship between an IV and a DV
What is special about the IV in the Ex Post Facto Design?
it cannot be manipulated or altered
-> because we look at how a particular characteristic, trait or past occurrence affects the dependent variable
What is the main character of the Ex Post Facto Design?
the groups of participants are determined by pre-existing conditions and events from the past
What research design is used when we investigate how teenagers weight influences their self-confidence?
Ex Post Facto Design
-> because researcher chooses participants based on a pre-existing characteristic (weight)
What is the IV if it is not manipulated?
it is observed as it naturally occurs
What do some types of IV commonly found in ex post facto designs include?
- Pre-existing conditions or characteristics (variables that exist prior to study, not manipulated by the researcher)
- Historical events or circumstances (events or conditions that have already occured before the study begins and ar enot under control of researcher)
What are 4 Characteristics of Ex Post Facto Design?
- No manipulation of IV
- Limited control over extraneous variables
- Exploratory and descriptive
- They cannot establish causal relationships due to the lack of experimental manipulation
What does limited control over IV cause?
low internal validity
What is internal validity?
the degree to which we can establish causal relationships, rejecting alternative explanations
What Advantage is there in the Ex Post Facto Design?
it allows researchers to study phenomena or variables that cannot be manpulated intentionally due to ethical or practical limitations
What are control techniques in Ex Post Facto Design?
- Matching
- ANCOVA
- Introduction of variables related to the DV
What is the purpose of Matching in the Ex Post Facto Design?
to create comparable groups based on certain characteristics or variables
-> reseracher cannot manipulate IV: matching allows to identify individuals who are similar on key variables that might influence the outcome being studied
What does Matching ensures in the Ex Post Facto Design?
that differences in the outcome variable are more likely to be due to the variable of interest rather than other extraneous factors
What is the purpose of ANCOVA in the Ex Post Facto Design?
it incorporates covariates into the statistical analysis to remove their effect on the DV
-> helps to clarify the role of IV by controlling for the influence of extraneous variables
What does ANCOVA allows researchers to do with covariates?
to statistically adjust for the effects of covariates, like pre-existing group differences or other variables that may affect the outcome
What is the effect of ANCOVA on internal validity?
It increases internal validity by reducing the influence of extraneous variables and clarifying the causal relationship between IV and DV
