2.4. Statistical analysis
COVID-19 INFECTION, REGRESSIONS
Sample characteristics were compared across different information groups to find out if there is any difference in their socio-demographical characteristics. The COVID-19 vaccine acceptance were compared between participants receiving different information as well as with different socio-demographical and psychosocial characteristics using cross-tabulation and chi-square test. Two multiple logistic regressions were applied for participants without (Model 1) and with (Model 2) COVID-19 vaccination records separately. The dependent variable was COVID-19 vaccine acceptance (or accept the vaccine earlier than actually did for those who received at least one dose of vaccine), and independent variables included three information blocks, namely gain/loss-framing on vaccine effectiveness, provision of subsidized physician consultation, and provision of cash incentives, and the participant characteristics including age, sex, whether having chronic conditions, education level, household income, perceived risk and perceived severity of COVID-19 infection, level of concerns over being quarantined, perceived effectiveness and perceived safety of COVID-19 vaccine. Vaccine acceptance rate was standardized for comparison across information groups according to age and sex distribution of the Hong Kong population aged 18–64 years. A direct standardization method was used to calculate the standardized acceptance rate by multiplying age- and sex-specific acceptance rate with population size of each of the age- and sex-groups in the reference population (i.e., Hong Kong population aged 18–64 years) (