A new foundation for methodological triangulation.
To show how triangulation with qualitative and quantitative methods can help confirm a theory to a greater degree than can either method alone. CONSTRUCT: Coherence view of theory structure and confirmation. Evidence helps confirm a theory if the theory is the most coherent way of accounting for the evidence, and one theory is more coherent than another insofar as it leaves fewer unanswered questions (and fewer unquestioned answers). The method of this theoretical essay is analytic. Analysis of the debate over methodological triangulation reveals presuppositions about theory structure and confirmation. Well-known arguments in the philosophy of science are presented to show that the presuppositions are false. The arguments provide evidence for the construction of an alternative, coherence model of theory structure and confirmation. Three consequences of the analysis are: (a) qualitative and quantitative methods do not produce theories with different structures; (b) qualitative and quantitative methods help to confirm theory in the same ways; and (c) used together, qualitative and quantitative methods can confirm a theory to a greater degree than the use of either method alone. A coherence of model of theory structure and confirmation supports a version of the blending view of methodological triangulation. Triangulation can provide completeness, abductive inspiration, and confirmation. This version of blending provides principles for resolving issues of methodological dominance and order, and it indicates how different methods can disconfirm theory.