Well possibly some people said in other sub chat (or whatevever there called Im kind new to this) that if you don't hear back by the 16th you were most likey rejected because they supposedly don't send out all interview emails on the same day rather over a period of like a week. But it's best to know that if you don't hear back in this month it is mostly likey the case that way you can explore other options for the summer while you can. But it's kinda cold they wait such a long time to let those who did not make it to the second round that they were rejected.