Founded in 1920, the NBER is a private, non-profit, non-partisan organization dedicated to conducting economic research and to disseminating research findings among academics, public policy makers, and business professionals.
Most iPhone purchasers at that time were high income, as it was an expensive new technology and the general consumer was happy getting ‘free’ phones from carriers. It was also costly and difficult to switch carriers. And further, I know from having worked in banking that it is very difficult to get accurate income data.
Taken together, my guess is this is just detecting the effect of higher income on lower birth rates.
Most iPhone purchasers at that time were high income, as it was an expensive new technology and the general consumer was happy getting ‘free’ phones from carriers. It was also costly and difficult to switch carriers. And further, I know from having worked in banking that it is very difficult to get accurate income data.
Taken together, my guess is this is just detecting the effect of higher income on lower birth rates.
Ding! Ding! Ding! We have a winner!