"The rapidly evolving political information environment poses significant challenges to democratic citizenship through e.g. the spread of disinformation, rise of hate speech, and lack of cross-cutting information. WHAT-IF aims to develop and critically assess an empirically grounded simulation functioning as a digital twin of the digital political information environment. This ‘WHAT-IF machine’ can be used to test the effects of potential policy and regulatory interventions on democratic citizenship, offering a tool for evidence-based policy making in the realm of (social) media quality and regulation."