Main aim of the project ist the calculation of a Social Return on Investment (SROI), following the corresponding concept of the Roberts Enterprise Development Fund (RDF). This concept intends to quantify economic, socio economic and social costs and yields of activities in social organisations. The economic costs and yields are measured as usually in a discounted cash flow approach. Complementing this economic value in the terminology of the SROI concept, a socio-economic value is calculated, which takes into account additional social costs and yields that can be quantified. Non-quantifiable qualitative aspects are described as well to grasp additional social yields of the organisations.This concept will be applied to four innovative projects for people who need support or long term care (e.g., elderly or handicapped people). Common characteristics of these projects are alternative housing arrangements offering an infrastructure for mutual neighbourgly help.