• Al Podgorski /Sun-Times Media
  • Rahm Emanuel during Friday’s debate in front of the Sun-Times editorial board.

“Rather than leading the country with people leaving, we’re leading the country with families coming back,” Rahm Emanuel said Friday during a mayoral debate at the Sun-Times.

The mayor was bragging about how Chicago has fared during his tenure. His claim about families flocking back to the city surprised me. Chicago’s population declined between 2000 and 2010, from 2.9 million to 2.7 million. Since then, the city may have indeed stopped losing population, but there’s not much evidence of growth, either: according to a 2013 census estimate, the population has increased by less than 1 percent since 2010.

After the debate, I asked the mayor’s campaign spokesperson, Steve Mayberry, for a source for Rahm’s assertion. He sent me a link to a press release about a “study” last year by the eminent demographic researcher, United Van Lines.

The press release showed that the moving company did indeed rank Chicago first among locales families moved to last summer. Chicago also ranked sixth among places families left.

But Chicago in this “study” doesn’t mean Chicago proper, because the rankings were of metro areas.

Melissa Sullivan, director of marketing communications for United Van Lines, told me the “study” tabulated moves to and from metropolitan statistical areas, not central cities in particular.

The Chicago MSA is vast, including eight Illinois counties besides Cook, four Indiana counties, and a county in Wisconsin, with a total population of 9.5 million.

So in this study, a family that moved from Atlanta to, say, Naperville would be counted as a family that moved to Chicago, because it had moved to our MSA. And a family that fled Lincoln Park for Wilmette would not be counted as a family leaving Chicago, because it had remained in the MSA.

And, yes, only families who used United Van Lines to move were counted in the “study.”

Other moving companies publish similar annual “migration” rankings. They give the companies a burst of free publicity when media write about the rankings—as Crain’s Chicago Business did in September, after United Van Lines announced last year’s “findings.” Emanuel also put out a press release then, trumpeting the results.

We don’t really know that the city of Chicago’s population is growing, even modestly, because the 2013 census figures are only an estimate. If the population is growing, we don’t know if it’s because of families moving back, or because of a rise in birth rates, or a decline in death rates. And we certainly wouldn’t know if it has anything to do with the mayor’s policies.

Does Friday’s stretcher by Emanuel mean you should be skeptical about other claims he makes about his administration’s triumphs? Yes.

And in the remaining debates, a suggestion for the mayor’s challengers: when Rahm boasts of some particular achievement, ask him, “Is that another of your United Van lines?”