In the New York Times, Emily Oster's research is cited, "A recently published paper in the American Economic Journal: Economic Policy adds to this discussion. Alice Chen, Emily Oster and Heidi Williams combined data from the United States with data from Finland, Austria, Belgium and Britain. As other studies have done before, they adjusted for differences in coding of very premature births. And as other studies found before, the United States has a significant infant mortality disadvantage. This study was different, however. It used microdata, or individual records of birth and death, as opposed to the aggregate data usually employed for cross-country comparisons."