design of any experiment is of utmost importance
because it has the power to be the most rigid type
of research. The
design, however, is always dependent on feasibility. The best approach is to control for as many confounding
variables as possible in order to eliminate or
reduce errors in the assumptions that will be made.
It is also extremely desirable that any
threats to internal or external validity be
the perfect world, all research would do this and
the results of research would be accurate and
the real world, however, this is rarely the case.
We are often dealing with human subjects,
which in itself confounds any study. We are also dealing with the restraints of time and
situation, often resulting in less than perfect
conditions in which to gather information.
are three basic experimental designs, each
containing subsets with specific strengths and
three basic designs include: (1) pre-experimental
design; (2) quasi-experimental design; and (3) true
They will be discussed below and as you will
discover, are addressed in order of effectiveness.