While there has been a resurgence of interest in policy implementation studies over the last ten years, there is still a lack of attention to process in governance theory and practice and the appropriateness of different conceptualisations of policy-action relationships. The first part of this seminar reports on research which explored the effect of politics on the value choices of senior public servants involved in the design and implementation of Australia’s National Disability Insurance Scheme. Our analysis shows that politics plays an essential role in facilitating implementation of a complex social policy that contains a number of incommensurable values because it allows these incommensurable values to co-exist, thereby avoiding the creation of a blocked hybrid. Furthermore, successful implementation of the National Disability Insurance Scheme depends upon continued co-existence because of the interdependence of these incommensurable values. The second part of this seminar considers the potential for new methodological approaches to the study of implementation issues which facilitate cross-case comparisons.