Public policy professor Solomon Hsiang, director of Berkeley's Global Policy Laboratory, joined Rachel Maddow to discuss the results of a study he led on the effectiveness of emergency policies intended to slow the spread of COVID-19.  He and his colleagues found that the measures -- including shelter-in-place, business closures, and transportation restrictions, and school closures -- prevented about 60 million COVID-19 infections in the United States and 285 million in China. Since so many people who become infected never get tested or diagnosed, the true number of cases avoided is inevitably much higher, and they estimate that figure in the six countries they studied to be more like 530 million. During the interview, Maddow reads back to Professor Hsiang one of the statements he made in the report, which particularly stunned her. He had said: "I don't think any human endeavor has ever saved so many lives in such a short period of time. There's been huge personal costs to staying home and cancelling events, but the data show each day made a profound difference." She asks him: "Do you mean that literally - that this might have been a collective human endeavor that saved more lives than anything else we've ever done?" He replies: "Absolutely. I think this is an incredible achievement. I mean, the ability to coordinate millions of people to stay home when they don't want to - to take on these hardships to save other people's lives - it's incredible."  Link to video here. For more on this research, see our press release at Berkeley News. Stories on this topic have appeared in more than 1,000 sources around the world now, including NPR and Reuters.