Explanation and prediction. Theories of this type combine the traits of II and III, and correspond to what many consider a “standard” conception of empirically-based theories.

D. I. K. Sjøberg, T. Dybå, B. C. D. Anda, and J. E. Hannay, “Building Theories in Software Engineering,” in Guide to Advanced Empirical Software Engineering SE - 12, F. Shull, J. Singer, and D. K. Sjøberg, Eds. Springer London, 2008, pp. 312–336. [Springerlink]