As part of the second quarter 2013 release of the Illinois Innovation Index, World Business Chicago used U.S. Census American Community Survey data to analyze young adult migration to and from the Chicago metro region. Below is a brief overview and methodology of that analysis. – by Tedd Carrison
In April, the U.S. Census Bureau released county-to-county migration data using responses from the 2010 5-year American Community Survey. In addition to migration totals, these numbers were divided into 15 age cohorts; the following analysis includes results for the two cohorts that span ages 25 to 34. This age range was chosen under the assumption that by age 25 many college undergraduates have graduated, so the data better represent professional, not academic, location decisions.
When looking at the 25-34 age cohort, the Chicago-Naperville-Elgin metropolitan statistical area (MSA) showed statistically significant net flows of residents from/to 28 other MSAs – in other words, accounting for the survey’s margins of error, 28 MSAs had outflows from Chicago that were statistically different from their inflows to Chicago. Of these 28 MSAs, Chicago attracted net gains from 12, and suffered net losses to 16. Chicago’s significant net gains came primarily from Midwestern college towns, while its significant net losses were largely to major western MSAs, including Los Angeles, Denver, Phoenix, Austin, San Antonio, and Portland (OR).
The following steps were taken to calculate the Chicago MSA’s migration totals:
- The ACS county-to-county data were joined to a table of MSA definitions released by the U.S. Office of Management and Budget in February 2013. Using the origin and destination county fields, the ACS numbers were grouped by MSA.
- Aggregate inflows, outflows, net flows, and margins of error were calculated for each MSA that shared a migration relationship with Chicago. The method outlined on page 52 (A-14) of the ACS General Users Handbook was used to calculate the aggregate margins of error.
- To determine statistical significance, the aggregate flows and margins of error were applied to the method outlined on page 56 (A-18) of the ACS General Users Handbook. If the inflow from an MSA was significantly different from the outflow to that MSA, the net gain/loss was included in the results described above. All margins of error and significance tests were calculated at 90 percent confidence, the Census Bureau’s standard level.
 Due to confidentiality concerns, the Census Bureau suppressed nearly one third of all records for the 25-34 age cohorts, representing nearly one quarter of all migrants.