The Understanding America Study HRS Wave 4 surveys are the fourth series of HRS surveys that UAS respondents are invited to. This wave replaces the UAS HRS Wave 3 in UAS185-190. Respondents currently participating in that wave will continue to do so until every survey in the wave has been completed.

New respondents who have not participated in the UAS HRS Baseline yet as well as respondents who completed the UAS HRS Followup more than two years ago are invited. The following HRS surveys are administered in the UAS HRS Wave 4:

• UAS 396: HRS sections A, B, C and D encompassing questions about the respondent and their household, their health and their mental abilities.
• UAS 397: HRS sections E, F, G and H encompassing questions about the respondent's family and how they care for them, their health and how it affects their daily life, other people they may help or who help them, and the place where they live.
• UAS 398: HRS sections J, J2, J3, M1 and M2 encompassing questions about the respondent's current job, their pensions and how their health might affect their ability to work.
• UAS 399: HRS sections N and P encompassing questions about the respondent's health insurance, any health services they use, and how likely they think various events will be.
• UAS 400: HRS sections Q, R and U encompassing questions about the respondent's income and assets (as well as verification of assets from previous waves(.
• UAS 401: HRS sections S and T encompassing questions about widowhood and any wills, trusts and life insurance policies the respondent may have.

Note that the above list excludes the HRS 2020 sections H2 (mortgage crisis) and W (Internet use).