Introduction to the Understanding America Study
The Understanding America Study (UAS) includes roughly 14500 adult participants (as of March 2025). That sample size, combined with recruitment specifically targeting underrepresented demographics, creates a pool notable for its breadth and depth, both necessary for precise results.
Adults living in households in the United States are invited to join the UAS panel using Address-Based Sampling (ABS) methods, in which addresses are chosen from postal records representing all addresses in the country. First, selected households get a postcard letting them know they’ve been chosen. One week later, they receive an invitation package by Priority Mail. This package includes: A letter from CESR Director Arie Kapteyn, explaining the study; $5 in cash; a promise of $15 if someone in the household completes a short, 10-minute survey—either online using a login code or by mailing back a paper version included in the packet; and a postcard they can return if they don’t want to participate, speak a language other than English or Spanish, or if they are unable to connect to the internet to take surveys.
If no one from the household responds or opts out after two weeks, we send another package that includes a reminder letter and another paper version of the survey, along with the same $15 offer for completing it. Two weeks later, non-responding households are sent a reminder letter which thanks them if they’ve already completed the survey and includes the login code. Finally, four weeks after that reminder, households who still haven’t responded receive a second paper survey and a “last chance” letter, along with the login code. The recruitment protocol has varied slightly over the years, changes and applicable dates are documented on the
Eligible individuals are all adults aged 18 and older in each sampled household. A household is broadly defined as anyone living together with the initial person who signed up to become a participant in the UAS. If a household is willing to participate but are not in possession of Internet access and/or a computer or tablet, one is provided for their use during the study’s duration.
The UAS also includes address-based samples of California and Los Angeles County, as well as special-purpose samples of Native Americans and Los Angeles County families with young children. The Native American sample relies on ABS recruitment targeting zip codes with a higher proportion of Native American populations; non-Native American primary respondents in these zip codes are not invited to join. The LA County families sample was recruited using birth records information from the State of California, which gives addresses to households where children were born during the previous five years. This is a small non-probability sample, and if participants are included in a UAS survey, they are provided with a zero weight.
The UAS elicits demographic information, such as age, ethnicity, education, marital status, work status, state of residence, family structure, etc., on a regular basis through the My Household questionnaire. New UAS participants complete this survey and are required to review and update their demographic information as needed every quarter before filling out more surveys.
When a research survey is ready for fielding, UAS panelists receive an email or postcard inviting them to participate. Included is a one-sentence description of the survey, as well as an estimate of the time it should take to complete, a deadline (if there is one) and the compensation they will receive for completion. Study members receive $20 for every 30 minutes of survey time. They are paid monthly via funds added to a prepaid card provided by the UAS. Study participants expect at least one survey each month and most welcome more.
At the end of each questionnaire, respondents are asked to rate their interest in the survey. Study members also participate in an annual survey measuring the performance of the UAS help desk and their overall experience in the study, including their preferred survey topics. Existing data from UAS surveys is available at no charge and only requires a data login. (Register here.)
In keeping with our commitment to transparency, we post the UAS sampling and recruitment protocol as well as response, recruitment and attrition statistics (which update daily). To facilitate methodological research around online probability panels, we also provide the UAS recruitment and participation files for download. These data are available to registered users under the Data Files and Products tab, on the Panel Recruitment and Participation Data page.