Over thirty years after Hood (1983) published his landmark book on policy tools, political and academic interest in them remains as high as ever. Many definitions, taxonomies and explanatory theories have been developed. However, public policy researchers have somehow managed collectively to overlook an entire class of policy-relevant tools. To policy instruments and procedural tools, we should now add the 'new' sub-category of policy formulation tools. In the 1970s and 1980s, certain types of policy formulation tool fell out of academic and political fashion and many observers assumed - understandably - that they were no longer relevant or could even be quietly forgotten.

Having looked - as we have done for the first time in this book - across the main types of policy formulation tool, we can confidently conclude that they are not in decline and nor have they been consigned to the dusty shelves of Self's (1981) backroom. On the contrary, they have expanded in number and their use has multiplied across many different venues. Recalling Salamon's argument that there has been a 'massive proliferation' in the tools of government, policy researchers should appreciate that the revolution in tool use was actually even more 'remarkable' than he claimed (Salamon 2002, p. 609). Why? Because he neglected to add the tools of policy formulation to his stock take.

Nevertheless, the existing literatures on policy formulation tools remain fragmented, not only across the main tool types but also different disciplines. For policy analysts, the divide between those tool experts seeking to pursue research 'on policy' and those preferring to undertake analyses 'for policy' seems even more pronounced than in other comparable sub-areas of policy analysis such as policy instruments. Indeed, the chapters of this book have more fully revealed that the debate amongst the policy analysts about tools can, on occasions, be as heated as that relating to policy goals and objectives (Mintrom and Williams 2013, p. 13), relating to both technical matters such as definitions and typologies, but also extending to more fundamental ontological and normative matters.

The tools summarized in the chapters of this book are very different to the ones that emerged in earlier eras, reinforcing the need for a fresh look. Indeed many have emerged out of, and been actively informed by, the critique emerging from the democratic theorists and the post-positivists. This book seeks to reinvigorate our understanding by drawing them back into the mainstream. For this, analysts require common concepts, parsimonious definitions and usable taxonomies. In this and the opening chapter we have sought to supply and then critically reflect on all three. We now invite readers to apply, test and critique them, perhaps using the theoretical perspectives outlined above; perspectives that we feel should, in time, be more fully integrated into broader theories of the policy process. Of course at the level of specific tools, debate about definitions, typologies and purposes will doubtless continue. We see that as a healthy sign, but believe that agreement at the broader level is now needed to generate a common and hopefully more fruitful research agenda, perhaps organized around our framework of actors, venues, capacities and effects.

What stands to be gained by embarking on a more systematic approach to the study of policy formulation tools? In Chapter 1 we suggested that there is potentially much more to add to our collective understanding of the tools themselves which, as repeatedly noted throughout this book, have often been studied in a rather isolated, static and descriptive manner. At the time of this writing it is very difficult to answer questions about tool choices and effects that Salamon challenged scholars of policy instruments to address many decades ago. It is also very difficult to work out how policy formulation tools interact with other tools and instruments (Howlett 2011, p. 27). Thinking more generally about forms of analyses for policy, the policy formulation tools literature has much ground to make up in relation to prescriptive advice on the selection and mixing of tools. At present there are no maxims (Howlett et al. 2014) of the type found in the policy instruments literature (for example, escalate slowly up the pyramid of intervention) or meta-tools to inform the design of tool packages. Clearly, inconsistencies between some tool pairings are more obvious than between others. MCA and participatory approaches do seem to mix more freely with one another than, for example, CBA and scenarios. But there is plenty of fresh work to be done on whether and indeed why this might be the case.

Second, in Chapter 1 we argued that a renewed focus on policy formulation tools can add to our collective understanding not only of policy formulation but public policy more generally. Of all the stages of the policy processes, policy formulation is arguably the one we know the least about. It is often complex, fluid and usually much less accessible to public scrutiny than other stages. Looking through the prism of tools is methodologically advantageous in the sense that, drawing on Hood (1983, pp. 115-131), it reduces complexity and permits comparisons to be made more easily across time, and between different policy areas and political systems. The chapters in this book have, we think, shown the potential of a 'tools approach' to shed new light on these issues. They confirm that the tools play a significant role in structuring policymaking activity and in determining the content of policy outputs and thus policy outcomes. The chapters also suggest that the tools are vital aspects not only of policy design, but also the nascent debate about policy capacities (Howlett 2011, p. 146).

Third, we have suggested that studying policy formulation tools more intensively may - paradoxically - add something to our collective understanding of politics; 'paradoxically' because the tools were originally conceived as a means to take the political heat out of policymaking. The chapters of this book have confirmed that the politics around policy formulation tools are, by their nature, often more subtle than those emerging around policy instruments, but they are no less important for it. Moreover, the chapters have shown that even if tool choices seldom make political headlines, over time they can have profound effects on the way problems are conceptualized and policy recommendations made to decision makers. They have also more fully revealed how they are used to control line agencies and depoliticize areas of policymaking. Policy formulation is the point in the policy process when the political commitment to 'do something' expressed during agenda setting runs into the constraints and the opportunities of the status quo. Long ago, Dahl and Lindblom (1953, pp. 16-18) argued that instruments lie at the very heart of the public policy process. Rather than debating in terms of grand ideologies such as capitalism and socialism, policy actors communicate in the more technical language of regulations, taxes and so on. A tools perspective offers insights into governing beyond formal rules, administrative systems and constitutions. Academics, scientists, policy consultants and think tanks were shown to play a determinative role. Matters of policy formulation are often not publicly debated, but the tools used and the effects they eventually generate undeniably involve questions of political power and the distribution of social values, and as such deserve to be a subject of analysis in their own right.

Finally, the chapters have suggested that bringing the tools into the mainstream of policy research may also help us to learn more about ourselves and our multidisciplinary field of policy analysis. To tell the story of policy formulation tools is to tell of the emergence and professionalization of policy analysis. From their origins in the 1940s, the popularity of the tools waxed and waned. They were originally developed by economists, statisticians and systems analysts to 'speak the truth to power' (Goodin et al. 2006, p. 7). As we pointed out in Chapter 1, their designers and advocates fell short in delivering upon their undoubted promise and they were conveniently forgotten about by many public policy scholars. When and why this happened is a story that deserves to be told as part of the broader 'turn back' to policy formulation tools.