Invest Through Behaviour reframes how capital decisions are made in social housing impact investment. Today, investment decisions rely on high-level financial and ESG indicators that assume impact rather than demonstrate it, and that obscure the real trade-offs between competing priorities. This project proposes a decision-support approach that treats neighbourhoods across London as a landscape of genuine compromises—balancing financial viability, social need, and housing demand—rather than collapsing them into a single misleading score. By keeping these priorities visible and comparable until the moment of choice, it exposes the trade-offs that define where investment matters most. The central contribution is the integration of behavioural metrics as measurable indicators, bridging the gap between planned impact and impact as it is actually experienced in lived urban reality.