Austin Nichols (PhD, Economics, University of Michigan-Ann Arbor) is a social science economics principal associate at Abt Associates who served as principal investigator of the Lessons Learned from Social Security Administration (SSA) Demonstrations project. He is an expert methodologist with 20 years of experience in the evaluation of disability policy, labor market, and education issues. Dr. Nichols has conducted studies for U.S. federal agencies including the Department of Labor, Health and Human Services, Housing and Urban Development, Veteran's Affairs, and Education. He has also worked under contract for state and local governments, and many foundations. In addition to publishing influential papers about disability policy, health, and labor markets, and producing technical reports on related topics, Dr. Nichols has presented at numerous conferences, and served as a discussant on research on disability policy over the last 20 years. At Abt, he provides technical and methodological guidance for policy evaluations across numerous policy areas, and regularly serves as principal investigator, director of design and analysis, or project quality advisor on Abt research projects. Dr. Nichols's expertise includes random assignment, quasi-experimental, and descriptive research design; evaluation technical assistance; survey design and testing; implementation analysis; statistical analysis of survey and administrative data; and dissemination of findings to academic and policy audiences. He was also the principal investigator for the Stay-at-Work/Return-to-Work project for the Department of Labor. Dr. Nichols co-authored Chapter 3 "Use of Demonstrations" and presented it with Robert Weathers at the Lessons Learned from SSA Demonstrations: A State of the Science Meeting. He co-authored the introductory chapter with Jeffrey Hemmeter and co-edited the Lessons from SSA Demonstrations volume with Jeffrey Hemmeter and Debra Goetz Engler. Jeffrey Hemmeter (PhD, Economics, University of Illinois, Urbana-Champaign) is the acting deputy associate commissioner in the Office of Research, Demonstration, and Employment Support at the Social Security Administration (SSA) where he helps design, conduct, and oversee research, evaluation, and policies related to disability and return to work. Dr. Hemmeter's research focuses on transition-age youth and Supplemental Security Income (SSI) and he has worked on several SSA demonstrations, evaluations, and studies, including as the lead on the Promoting Readiness of Minors in SSI evaluation. He co-authored the introductory chapter and co-edited the Lessons from SSA Demonstrations volume with Austin Nichols and Debra Goetz Engler. Debra Goetz Engler (MPA, Policy Research and Analysis, University of Pittsburgh) is a researcher in disability policy at the Social Security Administration (SSA). Ms. Goetz Engler currently serves as a supervisor in the Office of Research, Demonstration, and Employment Support where she leads teams conducting research and demonstration projects. She began her federal career in the research office at SSA as a Presidential Management Fellow, during which she completed an assignment at the Government Accountability Office. Prior to joining SSA, Ms. Goetz Engler worked with children, youth, and families, specializing in transition-age youth, in transitional living, foster care, and workforce development programs. Ms. Goetz Engler co-authored Chapter 9 "Lessons from Implementation" and presented it with Michelle Wood at Lessons from SSA Demonstrations: A State of the Science Meeting and she co-edited the Lessons from SSA Demonstrations volume with Austin Nichols and Jeffrey Hemmeter.