摘要:The study of firms’ decisions on open innovation has recently attracted the attention of scholars studying the process that firms follow from closed to open models. Extant research has acknowledged that firms tend toward open innovation models and has identified the optimum levels of breadth and depth of openness toward which firms should tend. Surprisingly, there is little evidence on how firms move toward open innovation and whether they follow scholars’ recommendations. In this paper, we investigate the adoption of the open innovation model, studying firms’ decisions on breadth and depth and switching behaviours over time. This paper provides a discussion of firms’ degree of openness and how firms structure and reassess their decisions on open innovation over time. This framework was applied to the Panel of Technological Innovation database that includes data on Spanish innovating firms for the period 2005–2013.