Lead the development of program cost models to support proposal design, translating program strategies into activity-based budgets that reflect realistic, competitive, and defensible unit costs (e.g., cost per beneficiary and cost per output, and - where prior impact evidence permits - expected cost per outcome), in collaboration with technical advisors, new business development teams, country offices, and monitoring, evaluation, research, and learning (MERL) colleagues where applicable. Plan, conduct and support retrospective economic evaluations of Save the Children programs - including cost-efficiency and cost-effectiveness analysis, bringing together financial data, program/MERL data, impact evaluations, and external evidence to produce a holistic picture of program performance, in collaboration with internal and external researchers, technical advisors and country office colleagues.