Her research interests center on American cultural and intellectual history, the history of the human sciences, the sociology of knowledge, and the history of privacy and the public sphere. She is the author of The Averaged American: Surveys, Citizens, and the Making of a Mass Public (2007), which explores the relationship between survey data—opinion polls, sex surveys, consumer research—and modern understandings of self and nation. The book was a New York Times Editors' Choice selection and one of Slate’s best books of the year as well as the winner of the President’s Book Award of the Social Science History Association and the Cheiron Book Prize. Most recently, she is the author of The Known Citizen: A History of Privacy in Modern America (2018).