Senior executives have to deal with a constant stream of what seem like urgent challenges, more than they can possibly deal with. But it’s not always clear when they need to jump in. When can they delegate? And what can they ignore?

Last year, HBR published a framework from Nitin Nohria, a professor at and former dean of Harvard Business School, to help leaders manage this barrage. Now that the business world is in an even-more daunting environment, I reached out to see if his thinking has changed.

Nohria is well aware of the limitations on leaders’ time. Several years ago, he and fellow HBS professor Michael Porter did an exhaustive study on how CEOs spend their days. It turns out that a full 33% of CEOs’ time is spent reacting to unforeseen events. That means they need to triage how they handle the firehose of incoming challenges. Read this HBR article to find out more