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Census 2020: Population Change in Dane County

Census 2020: Population Change in Dane County

With ongoing releases of data from the 2020 Census beginning this fall, planners and municipal staff are sounding a refrain heard once every ten years: what’s changed? Not surprisingly, Dane County was again one of the fastest growing counties in the state and added significant population over the past ten years. At this point we have general enumeration of population, households, and racial and ethnic statistics down to the Census block level. While we await the release of more detailed and descriptive statistics, let’s look at where population change is occurring around the region:

  • Population continued to decrease in rural areas far from village and city centers as it had from 1990 through 2010,
  • Population growth in first ring suburban communities around Madison continued from 2010 to 2020,
  • New development on the isthmus from 2000 to 2010 continued and accelerated over the past decade, bringing more new people, and
  • Older neighborhoods throughout the City of Madison saw a net increase in population as infill and redevelopment projects brought new housing units, countering the effects of household size decline and net population loss seen over the past few decades.

Population Decline

Before looking at where population growth is occurring, we need to touch on population decline. The maps presented show both population growth and decline. Growth is shown in blue shades and decline in orange. At first glance the maps seem to convey a sort of exodus or abandonment of rural areas around the county and many of the established neighborhoods within Madison. This is far from the reality. For one thing, rural census tracts are typically much larger than their urban counterparts. Applying color to such large areas is more visually impactful than the same color applied to a much smaller urban tract. The color scheme of the map also has a role to play. The diverging blue-orange color ramp was picked because it is more colorblind friendly, and it creates a strong contrast of those areas gaining versus losing population. However, “hot” colors carry a cultural meaning for many of us due to their association with warning, alarm, or emergency.

But more important than any design considerations is the effect of decreasing household size on our maps. Since at least the 1970s, household size has been on the decline. As a result, areas around Dane County with no new housing units constructed see a net loss in population. This net loss is also occurring in some areas where there is active infill or redevelopment. All told, population loss from 1990 to the present has rarely amounted to more than 10% (a few dozen to a few hundred people) of any Census tract’s population. The take-away is that population loss does not automatically imply disinvestment in a particular area of the county.

Development in the Center

One noteworthy shift in the past 20 years has been the surge in redevelopment resulting in population gains in areas that would have otherwise felt the effect of household size decrease. Downtown Madison and established neighborhoods around the city have had few, if any, wide open land for housing development for decades. However, dense infill and redevelopment beginning in the late 2000s has added thousands of residents in many parts of the city. 2020 Census data indicate that this trend accelerated over the past decade. And while it is not as readily apparent due to the size of Census Tracts in other communities, infill and redevelopment in places like Middleton and Waunakee has resulted in population increases in long-established central areas.

Development at the Edge

Unsurprisingly, some of the largest increases in population percentage-wise occurred at the edges of communities where there were few residents to begin with. These areas saw some of the greatest numeric increases in population as well, both because the quantity of developable land is higher at the edges of communities but also because many communities around the region are developing at higher densities and with a more diverse mix of housing types than they were just a few decades ago. Many of the areas with the greatest population increase over the past decade exist between larger communities: the land where the City and Town of Middleton meet the City of Madison, land in the Towns of Burke and Blooming Grove between Madison and Sun Prairie, and the Town of Westport bordered by Waunakee, Middleton, and DeForest/Windsor.

What the Future Holds

Dane County has added and will continue to add tens of thousands of new residents each decade. Where this population will live and how they will be accommodated are some of the most pressing questions the region will face.

Consumer preference and the economics of real estate development have shifted to favor variety in housing and efficiency of land use. The trends toward infill and redevelopment seen in established neighborhoods and downtowns around the region are likely to continue. Likewise, smaller lots, mixed land uses and housing types, and multi-family projects in greenfield areas will be an increasing share of new development.

Draft land use strategies recommended in the forthcoming Regional Development Framework reinforce these trends. The Framework recommends directing growth to centers and corridors, prioritizing growth within established areas, and designing development that promotes proximity of residences to jobs, goods, and services. Developing in this manner is the responsible way to accommodate the strong population growth that Dane County is likely to experience in the coming decades.

A Note About Census Geography

To compare the 2020 Census to past censuses we need to use consistent geographies. This is a challenge because Census geographies are ever-changing. New blocks, block groups, and tracts are created as physical development occurs and the population increases. Census tracts will split as the population in them increases. Even municipalities in 2020 are not the same as they were in past decades due to annexation and shifting borders. To compare apples to apples, we need “geographically standardized” data. A fantastic source of these data is the NHGIS.[i]

[i] From the NHGIS website:

NHGIS is one of several IPUMS data integration projects housed with the Minnesota Population Center at the Institute for Social Research & Data Innovation at the University of Minnesota. The NHGIS project is funded by grants from the National Science Foundation and the Eunice Kennedy Shriver National Institute of Child Health and Human Development.

Geographically standardized tables provide data from multiple times for a single census’s units. In tables that are standardized to 2010, all data describe 2010 census units. To allocate one census’s summary data to another census’s geographic units, NHGIS reaggregates data from the smallest source units for which the data are available (e.g., census blocks, if possible). Where a source unit intersects multiple standard units, NHGIS applies interpolation to estimate how the source unit’s characteristics are distributed among the standard units. NHGIS provides data for 1990, 2000, and 2010 standardized to 2010 census units.