Share on Pinterest The COVID-19 Event Risk Assessment Planning Tool produces risk estimates based on the size of a gathering and what county it’s located in. As COVID-19 continues to spread across the United States, public health officials are recommending people avoid large gatherings as well as wear masks and maintain a safe physical distance if you do. How the tracker works The new COVID-19 Event Risk Assessment Planning Tool can give you an estimate of the risk that someone at an event of a specific size in a specific county has contracted the new coronavirus. Say you’re 1 of 10 people going to a public event in Clark County in Nevada, an area that includes Las Vegas. One thing tools like this can do — in theory — is show that we’re making progress, and that compliance with public health measures is working.