The MPC has growing strength in population mobility and spatial demography. An active group of scholars is researching the causes, characteristics, and consequences of population mobility and examining the spatial dimension of demographic processes. This cross-disciplinary group of scholars comes from a wide range of disciplines, including geography, economics, statistics, sociology, civil engineering, computer science, public health, urban studies, public affairs and population studies. Most of these researchers are newly-hired early-career investigators.
The MPC has three new and forthcoming spatial infrastructure projects that promise to have a transformative impact on spatial demography:
- We are building a global map of subnational statistical areas that have a consistent footprint over time and are linked to census and survey microdata. Through IPUMS International, we have completed and released consistent footprint maps for 82 countries for 1960 forward to approximate the first administrative level in each country. We are halfway through processing the second administrative level, with expected completion in 2016. This project involved two steps: 1) scanning historical paper maps to identify the building-blocks needed to construct consistent geographic units and then 2) creating new microdata identifiers for those units. The consistent global map allows—for the first time—measurement of demographic change and movement for small subnational statistical areas across many countries.
- For the United States, we are developing integrated time-series data for measuring change in small areas, including new interpolated estimates standardized to 2010 boundaries for tracts, block groups, ZIP Code areas, and other levels. We have released 3,774 time series through the National Historical Geographic Information System (NHGIS) and are rapidly adding more.
- The TerraPop project, described earlier, allows easy interoperability of raster data, such as satellite imagery, with area-level data and population microdata. TerraPop is now available in preliminary form; a production version will be released in early 2016.
Over the next five years, MPC research on population mobility will leverage these new tools. The availability of consistent geographic data will facilitate studies on many related topics: the determinants of migration, migration flows and migrant stocks, migrant selection and composition, immigrants' assimilation and integration trajectories, and subgroups' health and economic outcomes. Within these broad parameters, we plan several specific research projects. Using TerraPop technology and consistent boundaries, MPC researchers will focus on intersections of population movement with the natural environment, to examine the implications of environmental and climate change for population mobility and health.
Importantly, this research program will include consideration of specific pathways (e.g., household livelihoods) through which climate change affects migration. MPC researchers will examine changing internal migration patterns in the United States. This work will use a variety of new spatial data sources—including NHGIS integrated time-series tables—to evaluate how changes in government policies and local labor markets have slowed internal migration and increased back-to-the-city migrations.