Departments: Letters to the EditorEffects of Selective Exclusion of Patients on Preterm Birth Test PerformanceJelliffe-Pawlowski, Laura L. PhD, MS; Rand, Larry MD; Ryckman, Kelli K. PhDAuthor Information Department of Epidemiology & Biostatistics, University of California, San Francisco, School of Medicine, and the UCSF California Preterm Birth Initiative, San Francisco, California Department of Obstetrics, Gynecology & Reproductive Sciences, University of California, San Francisco, School of Medicine, and the UCSF California Preterm Birth Initiative, San Francisco, California Department of Epidemiology, College of Public Health, University of Iowa, Iowa City, Iowa Financial Disclosure Laura L. Jelliffe-Pawlowski reports that she received support for this work from the UCSF California Preterm Birth Initiative (PTBI-CA) for this work and the March of Dimes Prematurity Research Center at Stanford University. Larry Rand reports that money was paid to his institution from and The Bill and Melinda Gates Foundation. Kelli K. Ryckman reports receiving funds from UCSF, Bill and Melinda Gates Foundation, the NIH and the HRSA. The other author did not report any potential conflicts of interest. Obstetrics & Gynecology: April 2020 - Volume 135 - Issue 4 - p 971-972 doi: 10.1097/AOG.0000000000003783 Buy Corresponding Article Metrics Corresponding Article In Reply Saade, George R.; Boniface, J. Jay; Burchard, Julja Obstetrics & Gynecology. 135(4):972, April 2020. © 2020 by the American College of Obstetricians and Gynecologists. Published by Wolters Kluwer Health, Inc. All rights reserved.