Table 2.

Time bins used for analyses.

Time Bin	Start	End	Duration	Description
T1	3/23/20	4/12/20	3 weeks	Overlaps with the beginning of significant institutional responses to the pandemic. Many schools and universities closed or went to remote education in mid- to late-March, and most US states implemented some kind of lockdown order or stay at home order/advisory during this period.
T2	4/13/20	5/3/20	3 weeks	Initial discussions and implementations of “re-opening” after lockdowns in many states, but case numbers and deaths were still rising in most parts of the country.
T3	5/4/20	5/24/20	3 weeks	Re-opening plans continued in this period. Case numbers and deaths were declining in some parts of the country, but still rising in others.
T4	5/25/20	6/14/20	3 weeks	George Floyd was killed on May 25, setting off nation-wide protests and a wide-ranging national discussion on race.
T5	6/16/20	6/22/20	1 week	The last week of data collection in the spring period. Initial examination of trends suggest that much of the increased stress and negative mood following George Floyd’s murder had resided by this time period.
T6	9/30/20	10/13/20	2 weeks	Our first period of daily data collection since June. This marked the end of a period where COVID cases had been down (relative to the spring or mid-summer) in most of the country and is mostly before they started to rise again in October.
T7	10/30/20	11/5/20	1 week	The US election was on November 3. Uncertainty about the result continued through November 6.
T8	11/7/20	11/13/20	1 week	The US presidential race was called for Joe Biden by all major networks on November 7.
T9	2/22/21	3/7/21	2 weeks	Our first period of data collection since November. This marked the beginning of vaccinations becoming available to older adults.
T10	4/4/21	4/17/21	2 weeks	Our final period of data collection before vaccines became available to all adults on April 19, 2021. This time bin was also selected to be well matched, seasonally, to the T1 assessment.