Introduction

This package is designed to provide easy access to the U.S. Census Bureau’s API (https://www.census.gov/developers/) in Python. It supports pulling data from the American Community Survey (ACS) and the Census Summary File, specifically:

This package handles the details of interacting with the Census API for you, so that you can focus on working with the data. It provides a class for representing Census geographies. It also provides functions for gaining further information about specific variables and tables and for searching for variables. Full documentation is available at https://jtleider.github.io/censusdata/.

The ACS (https://www.census.gov/programs-surveys/acs/) started in 2005. It provides information on a wide range of social, economic, demographic, and housing characteristics. Topics covered include income, employment, health insurance, the age distribution, and education, among many others. The ACS replaces the old Census long form, which used to be distributed to a subset of households responding to the decennial Census. The ACS produces survey-based period estimates. For instance, the 5-year 2011-2015 estimates are based on data collected during all 5 years. They are not simply an aggregate of 1-year estimates, and overlapping 5-year estimates (e.g., 2008-2012 and 2011-2015) should not be compared. The ACS provides margins of error to accompany all estimates. Margins of error are smaller for estimates based on more years of data.

ACS 5-year estimates are the least current but provide the greatest precision and are available for geographies of all sizes (https://www.census.gov/programs-surveys/acs/guidance/estimates.html). By contrast, 1-year estimates are the most current but the least precise and are only available for geographies with populations of 65,000+. In between are the 1-year supplemental estimates or, in past years, the 3-year estimates, both of which are for geographies with populations of 20,000+. The choice of which ACS estimates to use will depend on your needs for current data vs. data for a variety of geographies with greater precision.

The decennial Census counts every resident of the United States. The 2010 Census Summary File 1 provides information about each community’s population, including age, sex, and race distributions, as well as information on households and families. (Summary File 2 provides additional data for specific racial/ethnic groups.)

There are a number of facilities available for downloading Census data, including American FactFinder, the ACS summary files, and the Census DataFerrett. This package is designed to provide the following features not available elsewhere: