Table 2.

Summary of variables added to dataset during preparation and validation steps

Variable name	Variable definition
which_NCIPR	(1) NCIPR wave 1 February 23, 2021; (2) NCIPR wave 2 March 31, 2021
complete_binary	(0) incomplete (n=483); (1) complete (n=1,729)
why_incomplete	(1) complete (n=1,729); (2) survey administration error (n=338); (3) incomplete survey (n=145)
covid_self_report	(0) report no prior COVID-19 illness (n=65); (1) confirm COVID-19 prior illness (n=2,147)
DOB_age_out_of_range	(0) date of birth age = 18–100 years (n=2,157); (1) date of birth age = <18 or age >100 (n=55)
COVID_date_out_of_range	(0) Feb 2020 - March 2021 (n=2,192); (1) dates in range not selected (n=20)
quality_check_flag	(0) none (n=1,857); (1) ≥1 implausible response (e.g., 6’20” tall) (n=4); (2) ≥1 inconsistent response (What is your current age? [db_52] ≠ reported date of birth +/− one year) (n=68); (3) inconclusive (e.g., age or DOB response not provided) (n=283)
data_correction	(0) no correction; (1) typo in age or height; original data unchanged but [quality_check_flag] changed to ‘0’ (n=7)
excluded_sample	(0) included (n=1,584); exclusions filtered in the following order: (1) incomplete (n=145); (2) survey admin error (n=338); (3) [covid_self_report] = ‘0’ (n=65); (4) DOB provided out of range (n=46); (5) [quality_check_flag] = ‘1’ or ‘2’ (n=19); (6) COVID-19 illness date inconclusive (n=15)
age_calculated	Participant reported date of birth [db_2] converted to age in years