Immigration Correlations

Some Americans voice concerns that immigration is associated with social maladies, such as unemployment, poverty, and crime. LiveStories examined data across the 3,142 counties in the United States. We compared the percent of foreign-born residents in each county with a variety of other measures, both good and bad. 

We found no correlation between having a large immigrant population and having high unemployment or poverty—and the data actually shows a modest negative correlation for both homicide and drug overdose deaths.

Explore the data below. Select a measure, and the scatterplot chart will change to show how well it correlates to the percent of foreign-born residents (x-axis) for each county.

Data is for the 5-year period, 2013-2017. Note that only the 604 counties with data available for every measure are shown in the scatterplot. (See "About the Data" below.)

There are several ways to quantify correlation; here we’ve calculated Pearson’s correlation coefficient—also known as r—for each measure. Visually, you can think of the correlation coefficient as a scale that tells you: “how much do these data points form a diagonal line?” A perfect upward-sloping diagonal line has a coefficient of 1—for example, the scatterplot you see when the “Percent Foreign-Born” measure is correlated with itself. A diagonal line sloping downward, on the other hand, would have a –1 coefficient: a perfect negative correlation.

The chart below shows each measure's correlation coefficient against the foreign-born population. (To see if citizenship status made a difference, we also calculated the coefficients against each county's percent of non-citizens as well, which are shown in lighter blue.)

What factors are correlated with large foreign-born populations? High median home values, large county populations, and—perhaps not surprisingly—having a high proportion of residents who cannot speak English well.

Correlation is not causation. Any relationships between these measures and immigration may point to some deeper connection—or they may be entirely incidental. For example, the modest correlation between immigrant populations and higher incomes and home values does not by itself imply that immigrants enrich their communities. 

However, the assertion that immigrants bring crime and economic turmoil to their communities is not even based on any actual relationship in the data to begin with. 

About the Data

Homicide and Drug Death data were queried from CDC Wonder, by county. The rates are the reported age-adjusted rates per 100,000 population, covering the 5-year period from 2013 to 2017. The CDC does not report death rates with numerators less than 20. This cutoff tends to exclude counties with smaller populations. For drug death rates, only about half of all counties—1,565—had mortality data for this 5-year period; for homicides, only about a fifth—629—had data.

Population Percent Change data is from the Census Bureau's Cumulative Estimates of Resident Population Change, April 1, 2010 to July 1, 2018, queried via Factfinder. We included this measure to see how immigration might correlate with population growth. (The answer: modestly.)

All other data is from the American Community Survey's 5-year estimates, published by the U.S. Census Bureau. This data is available for all counties; however, it is estimated based on surveys, so data for small counties generally has higher margins of error. 

We used the following ACS tables: Median Age (B01002); Poverty (B17001); Unemployment (B23025); Bachelor's Degree or Higher (B16010); Median Household Income (B19013); Median Home Value (B25077); and Can't Speak English Well (B16004). For the English speaking measure, we summed all "Not well" and "Not at all" columns and calculated the value as a percentage. 

Note that some ACS tables only consider certain segments of the population, not the total population. English-speaking ability (B16004) is a percentage of the population 5 and older. Educational attainment (bachelor's degree or higher) is a percentage of the population 25 and older. The unemployment rate is a percentage of the civilian labor force. The poverty rate is a percentage of the population whose poverty status can be determined. (Some people, such as those living in certain group quarters and young children living outside families, cannot be assigned a poverty status.)

Although the interactive scatterplot chart only shows data points for 604 counties, the correlation coefficients were calculated based on data for all available counties for each pair of measures.