"This paper proposes a simple theory of a system of cities that decomposes the determinants of the city size distribution into three main components: efficiency, amenities, and frictions. Higher efficiency and better amenities lead to larger cities, but also to greater frictions through...

"We show that task juggling, i.e., the spreading of effort across too many active projects, decreases the performance of workers, raising the chances of low throughput, long duration of projects and exploding backlogs. Individual speed of job completion cannot be explained only in terms of...