Better Maps with Census Centers of Population

Jonathan Schroeder, IPUMS Research Scientist, NHGIS Project Manager

The best mapping resource no one’s using?

In the domain of U.S. population mapping, the Census Bureau’s centers of population may be the nation’s most underused data resource. Before I explain why, let’s cover some basics…

What are they? A center of population represents the mean location of residence for an area’s population, roughly the average latitude and longitude, adjusting for the curvature of the earth. For the last three decennial censuses (2000, 2010, 2020), the Census Bureau has published centers of population separately for U.S. states, counties, census tracts, and block groups.

Where can you get them? Through the Census Bureau website, you can download files containing the latitude and longitude coordinates for centers of population. To facilitate mapping and analysis, IPUMS NHGIS has transformed the coordinates into point shapefiles, available for download through the NHGIS Data Finder.

What are they used for? At the moment, not much! But there are dozens of settings where they’d be helpful. I’m hoping this blog will help get the word out, and if it does, you might now be reading this in some future age, marveling how we ever went so long without using them!

OK, how should we use them? In the case of statistical maps—my focus here—centers of population are wonderfully effective for placing proportional symbols. I share lots of examples down below to demonstrate, but first, let’s consider the general advantages of proportional symbol maps compared to a more common alternative: choropleth maps…

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IPUMS FAQs: How do the original occupation and industry codes map onto harmonized versions created by IPUMS?

By Kari Williams

As part of the IPUMS mission to democratize data, our user support team strives to answer your questions about the data. Over time, some questions are repeated. This blog post is an extension of an earlier series addressing frequently asked questions. Maybe you’ll learn something. Perhaps you’ll just find the information interesting. Regardless, we hope you enjoy it!

Here’s one of those questions:

How do the original occupation and industry codes map onto harmonized versions created by IPUMS?

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Using the MEPS-HC to Study Change in Adult Mental Health

By Julia A. Rivera Drew and Natalie Del Ponte

The Medical Expenditure Panel Survey-Household Component, or MEPS-HC, data are an invaluable resource for studying short-term trajectories in health, including adult mental health. An integrated series of the MEPS-HC data is available at IPUMS MEPS. Collected on the Self-Administered Questionnaire and, starting in 2019, the Preventive Self-Administered Questionnaire, the MEPS-HC includes two validated adult mental health scales. The Kessler Psychological Distress Scale (K6) and the two-item Patient Health Questionnaire depression screener (PHQ-2) are asked twice per panel, during interview rounds 2 and 4 (see Table 1). There are also two validated scales measuring health-related quality of life (HRQOL) that capture several interrelated health domains, including mental health. These include the Short Form-12 (SF-12) in 2000-2016 and the Veterans RAND-12 (VR-12) starting in 2017 (see Table 2 for VR-12 measures). For more information on the SF-12, see the section on SF-12 scoring on MCS and for more information on the VR-12, see ADDAYA.

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