A productivity expert says he stumbled across a 'counterintuitive' way to measure how much he accomplishes at work

He only feels good about himself if it's a very small number — say, four or five.

Duhigg is a New York Times journalist who researched the topic of productivity extensively for his 2016 book, "Smarter Faster Better." He shared the tidbit above with psychologist Ron Friedman during the Peak Work Performance Summit.

Here's Duhigg:

"This is counterintuitive, because it used to be that I would say, 'I sent 35 emails today,' or 'I sent 70 emails today, so it must have been a productive day,' but it's actually the opposite.

"If I have a day where I sent four or five emails, that means I got a bunch of other stuff done."

I could see where Duhigg was coming from. To me, there's no worse work-related feeling than getting to the end of the day and realizing I've checked nothing off my to-do list — even though I've been sitting at my computer all day.

In all likelihood, I've been fielding seemingly urgent messages from publicists, sources, and coworkers, without attending to the stuff I set out to do when I got to the office.

The broader theme behind Duhigg's observation is that modern workers tend to conflate busyness with productivity, when in fact, they're very different things.

"You can be busy all day long and never really be productive," Duhigg told Friedman. "You and I know that we can spend an entire day replying to emails and getting to 'inbox zero,' feeling like we worked every single minute and really not getting anything important done. You could do that your entire life."

Of course, breaking your habit of responding to every email in your inbox is harder — and often less practical — than it sounds.

But Duhigg's insights reminded me of something productivity expert Laura Vanderkam wrote in her 2015 book, "I Know How She Does It": "[Y]ou will never reach the bottom of your inbox. Better to realize that anything you haven't gotten to after a week or so will have either gone away or been thrust back upon you by follow-up messages or calls.

So let people follow up. Reward yourself, as Duhigg suggests, for doing real work and not the seemingly urgent stuff. In the long run, you'll be better off.