Policy instrument interactions in policy mixes: Surveying the conceptual and methodological landscape

Resolving a complex policy problem often requires a mix of policy instruments and thus the identification of the most promising instrument combination. However, the relevant terminology of instrument interactions in a policy mix has not been standardized, hindering a straightforward identification of superior instrument combinations. To address this challenge, the article defines the terminology necessary for detecting three different possible policy instrument interactions—namely synergistic, counter-productive, and additive effects. It identifies two approaches to analyzing instrument mix effects: the “effect-based” and the “effort-based” methods. It then discusses the practical advantages and limitations of each approach and elaborates on key methodological issues that policy scholars and practitioners face at each step of developing a new policy mix.