Which statement distinguishes a quasi-experimental study from a true experiment?

Question

The quasi-experiment does not use a control group.
The quasi-experiment uses multiple groups for comparison.
The quasi-experiment does not allow for manipulation of the independent variable.
The quasi-experiment does not use any experimental control.

Answer 1

Hello,

This question is a bit tricky, since quasi-experiments are very unique methods for studies.  The best way to answer this question is to look more into what makes a true experiment "true."

In true experiments, there is a control group.

In true experiments, there can be multiple groups for comparison (but confounding and statistical analysis become cumbersome)

In true experiments, the independent variable can be manipulated.

In true experiments, there is random assignment of the control and study group.

 

A quasi-experiment shares many of these qualities except that the quasi-experiment is unable to make random assignment.

 

Let's address this to the four options:

1) quasi-experiments do not use a control group.

They do, so it isn't 1).

2) quasi-experiments uses multiple groups for comparison.

They can and so can true experiments (although it isn't common)

It could possibly be 2), but very unlikely.

3) quasi-experiments do not allow for manipulation of the independent variable.

The quasi-experiment can manipulate the independent variable, since it can change the treatment group by varying degrees of treatment.

So it isn't 3).

4) quasi-experiments do not use any experimental control

The use of an experimental control would be random assingnment that would be used in true experiments.

The answer is most-likely 4).  True experiments have an experimental control, while quasi-experiments do not.

 

Hopefully this is helpful,

Hunter Haddad