Despite progress in technology, education, and workers’ rights, there continues to be a substantial difference in pay between male and female workers, even among those in similar jobs. While there are various hypotheses to explain this gender pay gap, academics and policy-makers increasingly support the view that it persists, in part, because workers often do not know what their coworkers earn. In fact, many companies have adopted “pay secrecy” policies that explicitly prohibit employees from discussing their pay, although in the U.S. this is technically illegal under the National Labor Relations Act of 1935.