3.1.1. Models Predicting Total Case Incidence
Models of key predictors of COVID-19 cases by census tract in
each of the two phases are presented in Figure 1 (left points, in
lighter blue). Overall, census tract characteristics consistently
associated with increased risk of COVID-19 cases included higher
population proportions of essential workers, those without health
insurance, Black or Latinx residents, and number of LTCF beds per
capita. By contrast, proportion of residents aged 20 or younger,
proportion of undergraduate students, and housing density were
significantly associated with decreased IRRs. Crowded housing, %
aged over 80 years, and proportion of American Indian and Alaska Native
(AIAN) residents were not statistically significantly associated with
tract-level COVID-19 case incidence rates. All associations were
statistically stable between Phase 1 and Phase 2 (i.e., there were no
changes in directionality or statistical significance), but a few
variables had substantive attenuations in magnitudes (i.e., more than a
10% change in point estimates toward the null): IRRs for % Black
decreased from 1.20 (95% confidence interval [CI]: 1.16, 1.24) in
Phase 1 to 1.04 (1.03, 1.06) in Phase 2, % Latinx decreased from 1.37
(1.30, 1.44) to 1.16 (1.13, 1.19), LTCF beds decreased from 1.39 (1.35,
1.44) to 1.06 (1.04, 1.07), and % undergraduates increased from
0.83 (0.80, 0.86) to 0.93 (0.91, 0.94).