worldbank.org (15.09.2025) Scaling up has become a rallying cry of social protection initiatives. The rationale for it is clear: with glaring coverage gaps globally and regionally, including nearly 2 billion people with no access to social protection in low- and middle-income countries, the extension of coverage is a key priority enshrined in an array of national and global commitments. Yet relatively little work has been devoted to examining how scale up happens. Understanding such an expansion process calls for examining the forces preventing it: these include, among others, fiscal constraints, possible political resistance, and limited delivery capabilities. A rich thematic literature has examined those constraints convincingly, including pointing out an array of compelling strategic, policy and operational implications for each theme. Yet, those factors taken individually can seldom offer a theory of change reconciling the forces shaping scale up processes. Some contexts with relatively adequate fiscal revenues may opt for high coverage of cash transfers (e.g., Indonesia), while others at comparatively similar or even more favorable financial positions may settle for lower levels of cash transfers coverage (e.g., Botswana); delivery systems can facilitate scale-up in some settings (e.g., Kenya), but there are cases where high scale-up was attained at relatively low levels of delivery capabilities (e.g., Yemen). This report aims to fill such a gap by emphasizing the interdependence of fiscal, political economy and delivery in explaining scale-up of cash transfer programs.