For many firms in the modern economy, their data is their most valuable asset. But how much is it worth? Columbia Professor Laura Veldkamp lays out six approaches to measure and value data. Each approach is guided by theory about how data is accumulated, traded, bartered or depreciated. While offering a simple overview of recent theoretical advances in data economics, the article’s focus is squarely on developing an arsonal of practical tools for empirical researchers, to measure data in new ways.