Deliverable 1.5 –Project Impact Assessment presentsthe quantitative and qualitative assessment of the social and economic impact of the Circular Economy practices implemented within the REFLOWproject’spilot cities. The deliverable reports on impactacross three phases: (i) exploring and describing change, (ii) evidencing and measuring change, and (iii) valuing and monetizing changewhich arepresented in thedeliverable’s three respective chapters: (i) Theory of Change, (ii) Key Performance Indicators, and (iii) Social Return on Investment.Firstly, thisdeliverable provides the final iteration of the pilot cities’ Theory of Change, including theiraccompanying narratives. Secondly, the achieved results of the pilot cities’ socio-economic and environmental Key Performance Indicators are reported. The deliverable closes off with presenting the Social Return on Investments for the pilot citiesat the level of a pilot solution. The results and outcomes from this deliverable provide the pathways to change, the social, economic, and environmental indicators to measure and evidence change, andthe social value creation of circular economy practices implementedwithin the REFLOW pilot cities whichsupport the business case for adoption of circular economy strategies by other European cities.