In the United States, if you have an Apple iPhone or iPad, it's a strong sign that you make a lot of money.<br />That's one of the takeaways from a new National Bureau of Economic Research working paper from University of Chicago economists Marianne Bertrand and Emir Kamenica.<br />"Across all years in our data, no individual brand is as predictive of being high-income as owning an Apple iPhone in 2016," the researchers wrote. <br />
