This paper discusses the new phenomenon of platform ad archives. Over the past year, leading social media platforms have installed publicly accessible databases documenting their political advertisements, and several countries have moved to regulate them. If designed and implemented properly, ad...

Data-driven campaigning has become a feature of political campaigns around the world. There is growing evidence that political campaigners at the elite and grassroots level believe that data matters for electoral success. This belief is having important consequences for the way that political...