Requiem for the Net Migrant

Abstract

Scores of papers published over the past two decades have reported on efforts to identify the determinants and project the consequences of interregional migration within various nations. Generally, such studies have sought to associate data on migration streams between pairs of regions and such variables as wage rates, unemployment rates, income levels, education, degrees of urbanization, and the distances separating origin and destination regions. Among the several ways of adjusting for relative differences in regional population levels, the division of stream totals by population size to define rates has been especially popular. When the stream is directional and divided by the origin "at risk population, it is called a gross migration rate or probability. When the difference between an in-flow and an out-flow stream is divided by the population experiencing both, the resulting measure is called a net migration rate, even though its interpretation as a rate is ambiguous.' rates rather than counts of the absolute numbers of events, even though some published studies ofnet migration have used the latter.Throughout this paper, I focus on analyses carried out usin

Estimates of Global Bilateral Migration Flows by Gender between 1960 and 20151

“…Third, estimates of bilateral ows provide a far greater depth to the understanding of international migration than can be obtained from net migration measures. As Rogers (1990) details, net migration statistics are fundamentally awed as they are based on a non-existent population. Further, they are sensitive to changes in both immigration or emigration patterns and hence their time series are often volatile.…”

“…Until recently net migration ow estimates produced every two years by the United Nations have served as the sole comprehensive source of global migration ow data. However, as with any net measure, they are susceptible to distorting and disguising the underlying patterns (Rogers, 1990) and hence are of limited explanatory use. More detailed measures, such as the immigration and emigration counts into each country, or country to country bilateral ows are far better equipped to explain and predict global migration trends.…”

Migration Flows: Measurement, Analysis and Modeling

“…A location with a large ratio (positive or negative) is an important node in the redistribution of the population -absorbing population when the ratio is positive, shedding population when it is negative. Effectiveness allows the analyst to compare migration loss and gain across states and groups of different sizes -something net migration cannot (Rogers 1990;Stillwell et al 2000). Identifying "migration effective" locations for different groups and arrival cohorts through time illuminates the roles of different places in the mobility system of migrants.…”

Reevaluating the Relationship Between In‐, Out‐, and Net Migration for Nonmetropolitan Counties: An Update on Beale's U‐Shaped Curve

“…Averaging over three years gives a better idea of longer-term trends, and helps remedy the problem of exceptionally lowhigh oneyear flows. Recent studies have cited problems with net migration measures (Rogers, 1990), and suggested an alternative-demographic effectiveness (Plane and Rogerson 1994). However, to maintain comparability with Beale's previous work, net migration measures were used.…”