Michael Lucci, Illinois Policy Institute Feb. 9, 2016, 3:33pm


Every year, millions of Americans leave the states in which they reside to move to other states. The U.S. Census Bureau calls this movement between the states “domestic migration.” And when a state loses more people to other states than it gains from other states, that is called net out-migration.

Since 1991, Illinois has lost between 48,000 and 105,000 people per year due to net out-migration. Yet in some years, the state’s overall population still grew, while in the other years the population shrank. For example, from July 2010 to July 2011 Illinois’ population grew by 20,600, yet from July 2014 to July 2015 Illinois’ population shrank by 22,200.

Many readers wonder how Illinois’ population can still grow when the state is constantly losing so many people to other states.

The answer is that there are other important components of population growth besides migration between the states. Those other components are positive for all American states, including Illinois. Every state has natural growth because there are more births than deaths. In addition, all states gain people, on net, from international immigration.

In the absence of major swings in domestic migration, an average American state grows in population due to a higher birth rate than death rate, along with gains from international immigration. Take Indiana, for example. From July 2014 to July 2015, Indiana’s population grew by 21,800. The components of Indiana’s population change were births (+83,800), deaths (-58,500), international immigration (+12,600), and domestic migration between the states (-14,900). Indiana’s population grew because natural growth combined with international immigration outweighed the minor loss from out-migration.

Over the same time period, Illinois’ population shrank by an estimated 22,200 people. That’s because Illinois’ large out-migration loss overwhelmed all the growth components. The estimated components of Illinois’ population change were births (+156,400), deaths (-104,200), international immigration (+37,700), and domestic migration between the states (-105,200).

These results add up over years and dampen what should be Illinois’ robust natural population growth. For the five years from July 2010 to July 2015, Illinois’ total population growth was a meager 28,400, compared with growth of 135,500 in Indiana. With respect to domestic migration, Illinois lost nine times as many people, on net, to other states as did Indiana.

Illinois had a net loss of 426,000 people to other states over those 5 years. This loss erased Illinois’ gains from international immigration (170,400) and nearly wiped out all of Illinois’ gains from natural growth (296,000). If Illinois had broken even on migration between the states, the Land of Lincoln’s five-year population growth would have been 450,000 instead of 28,400.

Indiana, on the other hand, had a net loss of 47,300 people to other states over 5 years, which was outweighed by the 57,500 people the Hoosier State gained from other countries. On top of that, Indiana had natural growth of 129,100 people, giving Indiana an estimated total population gain of more than 135,000.

Illinois’ out-migration crisis guts the natural population growth that the state would achieve if it were a more stable state like Indiana. Over the last five years, Indiana has averaged an annual loss of 9,500 people per year to other states, on net. This could be due to baby boomer retirees moving to southern states. Illinois, on the other hand, has averaged an annual loss of 85,200 people per year to other states, on net. That goes far beyond retirees moving south and reflects the serious jobs and growth crisis that faces the state.

Population growth and an expanding tax base are essential for Illinois’ budget. But Illinois lacks the population growth it needs because too many Illinoisans lack the job opportunities available only in other states.

The formula is simple: For Illinois budgets to work, the state must keep its people. And for Illinois to keep its people, it needs more jobs growth.

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