Marshall's student Pigou noted: It's all in Marshall. From a static point of view, this seems rather bold in a constantly changing world. However, this statement becomes more plausible in a dynamic context, where principles are subject to change. Indeed, over time, Marshall's concept of external...

We present experimental evidence that enabling access to universal early child care for families with lower socioeconomic status (SES) increases maternal labor supply. Our intervention provides families with customized help for child care applications, resulting in a large increase in enrollment...