Ricardian equivalence has been the subject of extensive empirical inquiry.
As research for a paper, he found himself analyzing data on productivity and wages, a typical empirical inquiry.
Conceptual frameworks can act like maps that give coherence to empirical inquiry.
Because conceptual frameworks are potentially so close to empirical inquiry, they take different forms depending upon the research question or problem.
Various empirical inquiries have been aimed at measuring academic self-efficacy.
The answer, in brief, is the method of empirical inquiry, at its best the method of science.
Anything like an adequate account of the method of empirical inquiry is out of the question here.
Scientists, in their boldest moments, speak of explaining away all the mysteries by empirical inquiry, leaving no need for ancient wisdom.
As scientists would be the first to insist, rational logos cannot address questions of ultimate meaning that lie beyond the reach of empirical inquiry.
Another suggestion is that case study should be defined as a research strategy, an empirical inquiry that investigates a phenomenon within its real-life context.