Essential resources like electricity and water can experience rapidly changing demand or supply while the other side of the market is unchanged. Short-run price variation could efficiently allocate resources at these critical times, but only if consumers exhibit short-run demand elasticity. The...

We document that recent quasi-experimental strategies for identifying advertising effects can be derived from a model in which ad decisions are made at a more aggregate level than conversion is measured. Next, we show that the identifying variation in one of these strategies, the Border...