The Panel Study of Entrepreneurial Dynamics (PSED) research program is designed to enhance the scientific understanding of how people start businesses. The projects provide valid and reliable data on the process of business formation based on nationally-representative samples of nascent entrepreneurs, those active in business creation. PSED I began with screening in 1998-2000 to select a cohort of 830 with three follow-up interviews. A control group of those not involved in firm creation is available for comparisons. PSED II began with screening in 2005-2006 with two follow-up interviews. The information obtained includes data on the nature of those active as nascent entrepreneurs, the activities undertaken during the start-up process, and the characteristics of start-up efforts that become new firms.