Two related propositions have been central in the recent debates on public sector reforms. The first of these is that the appropriate measure of institutional strength is the ability of public sector management systems to deliver ("functionality") rather than the institutional "form" or what these institutions look like. This is a central idea in the World Bank's Public Sector Management (PSM) Approach 2011-2020. Second, and consistent with this, is the recognition that the process of engagement matters in the sense that how problems, solutions, and reform approaches are identified matters at least as much as what the solution is. This suggests that development institutions should focus on bringing a broad range of stakeholders together and facilitate a process of collective problem and solution identification. Recent contributions to the literature describe a "Problem-Driven Iterative Adaptation" approach as a means of putting this idea into practice. While both of these propositions have considerable intellectual and intuitive appeal, they are based on an inductive logic and neither is currently backed with a large body of robust evidence. This paper contributes to this literature by documenting the experience of a civil service reform project -- the World Bank-financed Sierra Leone Pay and Performance Project -- the objective of which is to improve the performance of the civil service in Sierra Leone by targeting a narrowly defined set of critical reforms. The paper concludes that intensive, client-led engagement together with use of a results-based lending instrument provide a promising way forward on a difficult reform agenda.