I numeri della pandemia: istruzioni (e cautele) per l'uso

The contribution describes the role played by statistics in the management of the covid-19 pandemic in Italy. Data collection, choice of indicators, modelling are activities contributing to describe the infection spread, its impact on the population's health and to define containment strategies. Diffusion time of an epidemic is short and fast responses are needed in every field: from medical doctors who must save lives, to scientists who must find solutions to erase the effects of the infection. For data analyzers, a compromise between data accuracy and fast results is inevitable. As a consequence, result indicators have a degree of uncertainty, which should be managed and communicated to policy makers and the general public. Usage of statistics during the pandemic will be illustrated: how data were collected, which indicators and statistical models were used to describe the phenomenon and how results were communicated to the various stakeholders. Criticisms, as well as good practices, will be explored.