“…Differing from Rodrik's horizontal expansion, model development in macroeconomics appears, at least at the outset, to proceed along the lines proposed by Ylikoski and Aydinonat (2014), who emphasize the notion of a model family (see also Balzer and Dreier 1999). According to Aydinonat and Ylikoski, a model family is formed around a set of critical assumptions (the central mechanism), which remains the same within the family, and testing the robustness of the main results is essential to the empirical interpretability of the model family as a whole (see also Kuorikoski 2 Thus, when Bernanke and Gertler (1989), for example, formalized the financial accelerator in a general equilibrium framework they started a model family because several later papers used their framework.…”