Forum Comment Topic 1

In the textbook (de Vaus) chapter 3, the author describes various research designs. One design is "retrospective experimental design".

The  term "retrospective experimental design" seems unusual, in that I had thought a key attribute of the experimental design is that the researcher exercises control over the assignment of treatments to the experimental units through the process of randomization.

It would seem to me that any retrospective analysis could only be observational, as the researcher can in no way assign treatments to subjects.

In fact, the retrospective experimental design seems very similar to the cross-sectional or correlational design.

Also, de Vaus seems to suggest that surveys, because of the method of analysis and form of data, can be used for an understanding of causal relationships or links, whether or not the design is observational or experimental.

One of the points I came away with from HMS771 Analysis of Variance (and other statistics units) is that an experimental design allows inference of causality, observation allows inference of association

 If you can use de Vaus' article as an example (refer chapter 18, Putting it into Practice: a research example), the link he demonstrates is more of "association" rather than 'causality':

In the paper which the chapter refers to, Gender Differences in Religion: A Test of the Structural Location Theory", he states " the results show that the lower rates of female labor force participation are the major cause of their greater religious commitment". (my emphasis).

In the discussion section at the end of the paper though, he says, " the question remains as to why work force participation affects the religious orientation of females".

That seems to say, there is a correlation, but we still don't know what causes it.

----------------------------------------------------------------------------------

 I agree with Graham.  I find it difficult to distinguish between a cross-sectional (correlational) survey design, and a retrospective experimental design.  Both designs appear to rely on the a posteriori selection of groups.  Grouping of the subjects is based on the level of exposure to the independent variable.  The only possible distinguishing feature mentioned for the "retrospective experimental design" is in the attempt to match the groups with respect to other independent variables, in order to remove confounding.