This case study represents the first in a planned series of studies on the ‘The Role of Evidence Informed Policy Making in Delivering in Performance’. The case study is based on both interviews with key stakeholders and desk research. It focuses on the social investment approach in New Zealand, which is an evolving approach to thinking long-term and making informed choices on how best to improve people’s wellbeing. Social investment brings together different tools and approaches to good governance, building on the respective strengths of performance management and evidence informed policy making. At its core, social investment involves using data and evidence to understand customer needs from a person centric and long-term perspective, proposing innovative solutions that meet citizens’ needs and deliver financial savings, evaluating programmes to identify what works and what doesn’t, and publishing these results openly and feeding findings into the next set of decisions. The case study concludes with a number of recommendations for improving the social investment approach in New Zealand. These recommendations are also relevant to other jurisdictions trying to strengthen the capacity for evidence informed policy making.