Abstract This administrative supplement proposes to continue a high-frequency longitudinal survey of Americans’ experiences and behavior during the COVID-19 pandemic. The longitudinal survey was started on March 10. The survey will be conducted of respondents to the Understanding America Study (UAS), a probability-based panel of 8,500 adults representing the entire United States. Housed in the Center for Economic and Social Research, at the University of Southern California, the UAS employs an ‘Internet Panel,’ in which respondents answer surveys on a computer, tablet, or smart phone, wherever they are and whenever they wish to participate. Respondents are recruited through Address Based Sampling and receive a tablet and broadband Internet subscription if needed, thus facilitating coverage of the entire adult population 18 and over in the U.S. The set-up allows for an immediate and efficient transmission of data, which are quickly made publicly available through its online platform We will invite 7,000 UAS respondents to answer bi-weekly surveys (500 every day) through the rest of the year. We will report moving weekly averages that will be updated every night by incorporating the newest batch of responses. Thus, results will be based on a rotating sample of responses. Importantly, since the same respondents will be answering every other week, we will be able to track changes with much more accuracy than when one would draw new samples every week. Updated results will be posted on the UAS web-site every night. A questionnaire will measure (a) perceptions of coronavirus risk, (b) individual prevention behaviors, including use of a face mask, hand hygiene, avoidance of health facilities, and other forms of social distancing, (c) consumption of coronavirus information from various sources, (d) effects on the household’s financial situation and their consequences for physical and mental health, health care, psychological distress and substance use, and (e) coping behavior of households.