The authors thank three anonymous reviewers, the associate editor, and the editor for comments that significantly sharpened this paper; audiences at the NBER Organizational Economics meeting, Economics of AI conference, Strategy Science conference, Wharton Corporate Strategy and Innovation Conference, and Columbia Business School Management, Analytics, and Data conference for comments; Ed Glaeser, Claudia Goldin, Shane Greenstein, Bill Kerr, Frank Levy, and Bob Margo for feedback at early stages of our research on the automation of telephone operation; Ashish Arora, Sharon Belenzon, Victor Bennett, Wes Cohen, Bo Cowgill, Sharique Hasan, and Kristina McElheran for comments on this paper as it developed; Maggie Zhou and Jim Bessen for helpful discussions; Senan Hogan-Hennessy and Greg Saldutte for outstanding research assistance; Elizabeth Crowley, Jesse Benedict, Yves Kertesz, and Amanda LaFauci for help collecting the data; and Sheldon Hochheiser and the AT&T Archives and History Center for access to archival records, feedback, and fact checking. All errors are our own.
