The parameters of policy portfolios: verticality and horizontality in design spaces and their consequences for policy mix formulation

Policies increasingly come in complex packages and understanding the nature of design criteria for such portfolios is increasingly important. However, existing studies of policy mixes fail to carefully define the dependent variable of the inquiry. As a result, theorization of policy design has lagged, the cumulative impact of empirical studies has not been great and understanding of the phenomena, despite many observations of its significance in policy studies, has not improved significantly over the past three decades. This paper aims to revitalize this important aspect of policy design work and policy studies by distinguishing between mix types and their impact on policy formulation. It defines key types and subtypes of mixes based on the complexity of design variables such as the number of goals, the number of policies and the number of levels of government and sectors involved in the design of a policy bundle. The taxonomy is then used to assess the validity and applicability of oft-cited but under-examined portfolio design principles and precepts.