1. Introduction
Policy tools, or the techniques through which governments generate, evaluate and implement policy options, have been the subject of research throughout the history of the policy sciences. The study of the field dates back to Lowi and others who developed many typologies and theories on the subject in the period 1950-1980 as well as works such as Hood, Salamon, Linder and Peters; Peters and van Nispen, Schneider and Ingram, and Lascoumes and Le Gales in the era since then.
This work is important work for policy scholars interested in explaining policy dynamics as well for those adopting a policy design perspective (Howlett 2019). In fact, it can now be argued convincingly that an instrument-based approach can better enlighten the nature of policy dynamics, from a prescriptive point of view, and assist policymakers in taking more effective decisions than can a purely input-based approach.
Despite much effort, however, many fundamental issues remain unknown or under-studied and there are key elements concerning individual policy tools. Central to all these studies is the need for a clearer understanding of the policy instruments arrayed in a policy mix, as well as how these tools relate to each other when combined, what impact this combination has on the effectiveness of policies both when enacted and how these packages or portfolios evolve and change over time.
It is time to take inventory of what is known and unknown about policy tools. This paper presents a survey of informed thinking about policymaking, policy processes, the manner in which tool choices are made, and the ways that tool bundles evolve over time. It examines four clusters of basic issues in the field which require additional research. The level of knowledge about each of these issues is established, forming the basis for a multi-pronged research agenda into the subject.