Theoretical validity ask if the account of the research is valid in terms of the theory of
what is happening in these groups. “...the issue is the legitimacy of the application of a given
concept or theory to established facts, or indeed whether any agreement can be reached about
what the facts are” (Maxwell, 1992; p. 293). There are two issues in this specific research: Is
the use of Toulmin’s argument structure valid, and do students co-construct a problem solution?
One might even ask if constructivism itself is a valid world-view. The theoretical starting point
of this research was that Toulmin is valid and that students do co-construct a solution. For nearly
40 years, Toulmin’s argument structure has been use in rhetoric, debate, and logic. Although
many have “argued” with some of his ideas, the fundamental assertion that a formal argument
structure contains Claims, Grounds, Warrants, and Backings is generally accepted. That
acceptance is supported by the number of people and disciplines that have used it. Likewise,
there is a vast body of research literature on constructivism in science. It is a view of science
learning that is commonplace. In both cases, I believe these theoretical frameworks have stood
the test of time because they work. That is a bit like theories in physics. Those that survive do
so because they are able to describe existing phenomena and predict new behavior.
Generalizability Validity
This type of validity asks if the account can be extended to other persons, times, or
settings. What generalizability really asks is if this account can be used to make sense of other
situations and settings. Qualitative studies are not usually replicated, but the extension to other
settings is important to consider. I will more directly address the issue of generalizability in my
discussion of suggestions for future research and suggestions for curriculum and instruction.
SIGNIFICANCE OF THE RESEARCH