Policy analysis has always been interested in better understanding and improving the sets of policy tools adopted by governments to correct policy problems. Comparative policy studies have contributed much towards clarifying the nature of the processes of policy analysis and policy formulation which result in the construction of these policy portfolios. Past studies have helped clarify the role of historical processes, policy capacities and design intentions in affecting policy formulation processes - from design to non-design ones - and more recently have begun to articulate basic principles for better policy designs. Effectiveness in this work has been evaluated at three levels of consideration: that of the analysis of effective formulation environments or spaces that are conducive to the design of effective policies; through studies of how effective policy tool portfolios or mixes can be constructed to effectively address complex policy goals; and through a more specific and traditional focus upon what constitutes the effectiveness of particular types of policy tools within a mix. Each of these contributions is examined in this article.