PROST (Pension Reform Options Software Toolkit) is a software-based projection tool developed by the World Bank to forecast future pension spending. IHP researchers, Ravi Rannan-Eliya and Aparnaa Somanathan, visited PROST development team at World Bank Headquarters to share notes on the development of projection models for social spending. The IHP team discussed their experience of building actuarial cost projection models to forecast future health spending, and gave feedback on the PROST team's ideas for adapting the PROST model to forecast health sector spending.