Construction grammar organizes its basic elements of description, its constructions, into networks that range from concrete, lexically-filled constructions to fully schematic ones, with several levels of partially schematic constructions in between. However, only few corpus studies with a constructionist background take this multi-level nature fully into account. In this paper, we argue that understanding language variation can be advanced considerably by systematically formulating and testing hypotheses at various levels in the constructional network. To illustrate the approach, we present a corpus study of the Dutch naar-alternation. It is found that this alternation primarily functions at an intermediate level in the constructional network.