Suppose one has 40 or 50 survey questions for an exploratory analysis of a phenomenon, several of which are intended to be dependent variables, but most independent. A MLR is conducted with e.g. 15 IVs to explain the DV, and maybe half turn out to be significant. Now suppose an interesting IV warrants further investigation, and you think you have collected enough data to at least partially explain what makes this IV so important to the primary DV. Perhaps another, secondary model is in order... i.e. you'd like to turn a significant IV from the primary model into the DV in a new model.
Is there a name for this regression or model approach? It is not exactly nested, hierarchical, or multilevel (I think). The idea, again, is simply to explore what variables explain the presence of IV.a in Model 1, by building Model 2 with IV.a as the DV, and employing additional IVs that were not included in Model 1 to explain this new DV.
I am imagining this as a sort of post-hoc follow up to Model 1, which might sound silly, but this is an exploratory social science study, so some flexibility is warranted, imo.