Ex Post Facto Designs

Question 1

We simply observe what already has happened - we can look at the difference between groups or the correlation between variables.
The researcher goes in reverse, searching back for likely factors that brought about those differences
The researcher takes the effect (or dependent variable) and examines the data retrospectively to establish causes, relationships or associations, and their meanings
It is not possible to control variables in advance of the experiment or during the experiment

Question 2

Ex post facto research is a method of teasing out possible antecedents of events that hace happened and cannot, therefore, be controlled, engineered or manipulated by the investigator
Researchers can only report what has happened or what is happening, by trying to hold factors constant by careful attention to sampling
Independent variables cannot be manipulated.
The researcher is in the realms of probabilistic causation, inferring causes tentatively

CAUSATION CANNOT BE DEMONSTRATED

Question 3

They are possible in circumstances where the more powerful experimental method is not possible:
It is not possible to select, control and manipulate the factor necessary to study cause-and-effect relationships directly
When the control of all variables except a single independent variable may be unrealistic and artificial, preventing the normal interaction with other influential variables
When laboratory control for many research purposes would be impractical, costly or ethically undesirable

Question 4

The research on cigarrette-smoking and lung cancer
Studies of teachers characteristics
Studies of teacher characteristics
Studies examining the relationships between political and religious affiliation and attitudes;
Investigations into the relationship between school achievement and independent variables such as social class, ethnicity, gender and intelligence

Question 5

It can be used to study groups which are similar and which have had the same experiencia with the exception of one condition, and here the effect of the one differing condition on the dependent variable can be assessed
It is a form of experiment, but without the stringent control of a true experiment
There are control and “experimental” groups
BUT: there is little or no rigorous manipulation of the independent variables or conditions
There is no random allocation of subjects to groups

SO:
Any inferences of causation are tentative