Lively Minds is an NGO that helps LMIC governments deliver quality early childhood development at scale by activating the power of parents. Across the four school years from 2021-2025. Lively Minds supported Government of Ghana to deliver a programme across 64 districts and 3,447 schools. The roll-out took place in staggered cohorts – where 6 new districts entered the programme each school term, and then received termly support from Lively Minds terms for 3 years. Randomised evaluation has found that the programme in Ghana increased overall child cognition. Lively Minds would like to express those impact results as cost per unit of learning and be able to answer the question "what does an extra $100 achieve?" for evidence-led funders. The cost-effectiveness measurement should be based on the total number of children reached over the full 5 years and the total cost over these 5 years. The impact and cost data needed for the cost-effectiveness analysis (CEA) exist but are spread across programme monitoring files and finance files that were never designed to be joined. The monitoring files also vary significantly across programme phase and changed slightly across the different school years.