The average effectiveness of local migration exchanges

We develop a measure of the average effectiveness of migration exchanges with destinations, for local origins. We also decompose this new measure into components summarising the average effectiveness of a region's exchanges with places for which it has net out‐migration, and places for which it has net in‐migration. This makes it possible to define regions that are effective exchangers, balanced exchangers, effective gainers, or effective losers, with respect to their migration exchange patterns. This is discussed in the context of the measure's ability to add insights to migration theory. In addition, we provide an application of the approach to intercounty migration for counties in New York State.