“R” you getting this? Factors contributing to the public’s understanding, evaluation, and use of basic reproduction numbers for infectious diseases

We (1) examined the effects of evaluative labels and visual aids on people’s understanding, evaluation, and use of the COVID-19 reproduction number (or “r-number”), (2) examined whether people’s perceived susceptibility and (intended) adherence to preventive measures changed after being exposed to the r-number, and (3) explored whether these effects and changes depended on people’s numeracy skills. In an online experiment, participants from a large Dutch representative sample (N = 1,168) received information about the COVID-19 r-number displayed on the corona dashboard of the Dutch Ministry of Health, Welfare and Sport. The r-number was either presented with or without a categorical line display (i.e., evaluative label) and with or without an icon-based tree diagram (i.e., visual aid) explaining how the number works. Regarding people’s use of the statistic, we measured perceived susceptibility to COVID-19 and adherence (intention) to five preventive measures before and after exposure to the r-number. After exposure, we also measured participants’ understanding, perceived usefulness, affective and cognitive evaluation, and objective numeracy. About 56