Some like Michael Porter propose that strategy is driven mostly by the external environment. Review Porter’s Five-Forces Model and see if you agree. Is it mostly driven by external environment? In the other camp are the resource based view proponents of industrial organizational theory. The proponents of this view believe that strategy is driven by the firm’s internal environment. What are the external environment view and the internal environment view? Is one environment more important in driving strategy or is it really a combination of both environments?