The U.S. adopted a nationality-based immigration quota system in the 1920s to reduce the inflow of Eastern and Southern Europeans (ESE) and to preserve the ethnic character of the nation. But these quotas may have had unintended negative consequences for American science and innovation by keeping out scientists and inventors from these ethnic groups. To what extent did the quotas prevent foreign-born scientists from entering the U.S. and to what extent did native-born scientists become less productive as a result of not being able to work with foreign-born colleagues? To what extent did these quotas slow the pace of scientific knowledge development and innovation over the long run? Economist Petra Moser posits that the immigration restrictions of the 1920s may offer lessons for immigration policy today. She and her collaborators have assembled and digitized a dataset with detailed information (including date and place of birth, naturalization records, education and employment histories, discipline, and research topics) on over 80,000 American scientists from 1921 and 1956. The data have been linked with patent records and will be augmented with information on publications and collaborations to investigate the effects of the quotas on scientific productivity (e.g., number of scientists in the field, collaborations, and publications) and patent applications of U.S.-born scientists and inventors.