The daytime population in cities, counties and other areas changes due to commuting. The daytime population in Manhattan, New York County, increases by 95% during the day; the daytime population of Redmond, WA (Microsoft) increases by 111%; details below. Daytime population change impacts on decision-making relating to business opportunities, security, transportation management and wide-ranging issues. This section is focused on using daytime-related population to facilitate decision-making.
The concept of daytime population refers to the number of people who are present in an area during normal business hours, including workers. This is in contrast to the resident population present during the evening and nighttime hours. Information on the expansion or contraction experienced by different communities/areas between nighttime and daytime populations is important for many planning purposes, including those dealing with market size, trade/service areas, transportation, disaster, and relief operations.
The following tables/graphics show the ten counties and ten cities with 50,000 population or more that experience the largest percent change due to commuting. See 9th column %DayPop.
Use this interactive table to examine characteristics of counties and cities/places for the U.S. overall, by selected state and/or by population size class. The above graphics were developed using that table. Column headers in the above graphics are defined in that section. These data are based on 2010 ACS 5-year estimates and will update in December 2013. These data are the first commuter-adjusted population estimates based on the American Community Survey (ACS) and the first commuter-adjusted population estimates since Census 2000.
In the interactive table section, go through the step-by-step example for Texas substituting your own state of interest. For example, Shawnee has the highest percent population decrease among Kansas cities 50,000 and over while Overland Park has the highest percent population increase. These two Kansas cities are both in Johnson County in Kansas City metro.
Net Importers of Labor — the Employment-Residence Ratio
The Employment-Residence (E-R) Ratio is a measure of the total number of workers working in an area relative to the total number of workers living in the area. The E-R Ratio is a rough indicator of the jobs-workers balance in an area, although it does not take into account whether the resident workers possess the skills needed for the jobs that are available. E-R Ratios greater than 1.00 occur when there are more workers working in the area than living there. These areas can be considered as net importers of labor. View the E-R Ratio for any city or county in the interactive table. The E-R Ratios are shown in the rightmost columns in the above graphics.
Visual Analysis of Daytime Population Patterns
The following graphic shows the Kansas City MSA (brown boundary) with county labels. Cities are shown with E-R colors: orange: <0.8 E-R; yellow: 0.8 to -1.2 E-R; green: 1.2 or more E-R. Cities with an E-R ratio of 1.2 or higher (green fill pattern) means that there are 20 percent more workers working in the city than living in the city. The CV XE GIS software and the daytime demographics dataset can be used to visually examine areas of interest.
An upcoming post will cover updated, more recent data. An ACS 2011 update is planned for December 2013; an ACS 2012 update is planned for spring 2014. These estimates are now being prepared annually and will evolve into an annual time-series. The time series will facilitate longitudinal analysis of the daytime population and commuting patterns.