Table 4.
Phase 3 experiment results comparing intervention and control groups (February-March 2021; n=1314).
| Outcomesa | Control (n=668), n (%) | Intervention (n=645), n (%) | Effect estimate (95% CI) | P value |
| Testing intentions (self—if symptomatic next 4 weeks; 7=strongest intentions) | 5.8 (1.6) | 5.8 (1.6) | 0.07 (−0.09 to 0.22) | .40 |
| Self-isolation intentions (7=strongest intentions) | 6.2 (1.2) | 6.1 (1.3) | −0.03 (−0.16 to 0.10) | .63 |
| Knowledge total score (count/6)b | 5.5 (0.9) | 5.4 (1.0) | 0.98 (0.94 to 1.03) | .42 |
| Perceived risk (5=highest perceived risk) | 2.8 (0.8) | 2.8 (0.8) | −0.01 (−0.10 to 0.08) | .79 |
| Threat to Australia (10=very serious threat) | 6.7 (2.4) | 6.7 (2.4) | 0.04 (−0.21 to 0.29) | .77 |
| Self-efficacy (7=highest self-efficacy) | 5.8 (1.0) | 5.7 (1.1) | 0.00 (−0.11 to 0.11) | .96 |
| COVID-19 stigma (7=highest stigma) | 3.4 (1.2) | 3.6 (1.3) | 0.08 (−0.05 to 0.21) | .25 |
| Distancing intentions (7=strongest intentions) | 6.3 (1.1) | 6.2 (1.2) | −0.03 (−0.15 to 0.08) | .56 |
| Hand washing intentions (7=strongest intentions) | 6.4 (1.0) | 6.4 (1.1) | −0.04 (−0.14 to 0.07) | .49 |
| Mask wearing intentions (7=strongest intentions) | 6.0 (1.4) | 6.0 (1.4) | 0.02 (−0.13 to 0.16) | .81 |
| Follow-up: Self-reported testing behaviorc | 39 (9.4) | 39 (10.5) | 1.00 (0.67 to 1.51) | .99 |
| Follow-up: Testing intentions (7=strongest intentions) | 5.8 (1.5) | 5.7 (1.6) | −0.10 (−0.30 to 0.11) | .36 |
| Follow-up: Testing intentions (controlling for baseline intentions) (7=strongest intentions) | —d | — | −0.11 (−0.30 to 0.08) | .26 |
| Follow-up: Self-isolation intentions (7=strongest intentions) | 6.2 (1.2) | 6.1 (1.2) | −0.10 (−0.25 to 0.06) | .24 |
| Follow-up: Self-isolation intentions (controlling for baseline intentions; 7=strongest intentions) | — | — | −0.05 (−0.20 to 0.09) | .47 |
aContinuous outcomes were analyzed using linear regression to estimate marginal mean differences.
bCount variables were analyzed using Poisson regression to estimate relative risks.
cDichotomous outcomes were analyzed using generalized linear models with a modified Poisson approach (log link and robust SEs) to estimate relative risks.
dNot available.