A few years ago, New York Times investigative reporter Hannah Dreier ’08 obtained a swath of data on the locations of children immigrating to the United States without their parents — a demographic easily targeted by unscrupulous employers. She dialed around in search of anything that could point to whether these children were working underage, but each call resulted in the same conclusion: no one claimed to know anything. So, she put down her phone, hopped on a plane, and traveled where the data pointed her. Within a day or two at each location, she found and interviewed migrant children…