The buzzy concept of "grit" -- made famous by University of Pennsylvania psychologist Angela Duckworth, who won a MacArthur Fellowship for her work on the topic and whose TED Talk on it has been viewed more than eight million times -- is most commonly associated with schools.

In recent years, Duckworth's concept, which says that a combination of perseverance and passion helps predict a person's success, has become both a popular and controversial idea in the education world. Some schools have even rushed to adopt ways of measuring it and testing for it -- an idea to which Duckworth, a former teacher herself, is opposed. "Don't grade schools on grit" was the headline of a recent New York Times op-ed she wrote.

But in her new book, "Grit: The Power of Passion and Perseverance," Duckworth writes about "grit" in many other settings: on the athletic field, in the military and in business. She interviews or highlights how leaders from a variety of fields -- JPMorgan Chase CEO Jamie Dimon, Seattle Seahawks head coach Pete Carroll, UNC-Chapel Hill women's soccer coach Anson Dorrance, Philadelphia Mural Arts Program executive director Jane Golden -- think about the concept of grit or have developed cultures that focus on them.

We spoke with Duckworth, who also founded Character Lab, a nonprofit that aims to advance research on character development, about why she thinks leaders shouldn't measure grit in high-stakes situations, her response to some of the criticism her ideas have received, and why she shares her rejection letters with the people who work for her. The interview below has been condensed and edited for space and clarity.

What’s it like to win the MacArthur Fellowship — often called a "genius grant" — when you heard your father say, growing up, “you’re no genius,” as you wrote in the preface of your book?

I was of course elated and grateful and all those things. But as soon as those emotions got a little bit under control I thought back to my dad. I knew he would be proud of me because he’s so interested in these kinds of outward accomplishments. Those early conversations about "you're no genius" -- it couldn't be avoided that those would leap to mind and the irony would make itself particularly salient.

As I said in the book, particularly in the last chapter, I have a 'growth mind-set' about my parents, too. The father I had as a little girl was not the same father I had as a teenager, or as a young woman in her 20s or now a woman in my 40s. My dad was not a still shot. My dad also grew up, like every parent does. I think he was both genuinely proud of me, and also, I think he had a slightly wiser perspective on life by that point.

You mention 'growth mindset,' a term from Stanford psychologist Carol Dweck's work. Can you explain what that means?

A growth mindset is having a belief -- a theory, if you will -- that the nature of human abilities is that they are malleable, not fixed. In the most general terms, having a growth mindset is believing that people are by nature learning, growing creatures.

Indeed, one of the arguments of your book is that you can grow 'grit.' But let's define the concept first.

I think that the most succinct definition of grit is stamina. The heart of grit is really about sticking with things, as opposed to dropping out of them. There's two ways that’s important. One is stamina of your effort: You keep trying, even when things are going badly. Part of grit is stamina of your efforts in the face of adversity, but there's also just the everyday stamina of, say, getting up at 4:30 in the morning and just going to the pool again or sitting down at your computer and working.

There's also stamina in your passion. One thing that's true of gritty people is they love what they do and they keep loving what they do. So they're not just in love for a day or a week. People who are really gritty -- they're still interested. [New York Times crossword puzzle editor] Will Shortz is still interested in crossword puzzles. He's been doing crossword puzzles since he was eight. He says if you're bored of puzzles, you're bored of life. Each one is new. That is stamina in your interest.

Most people who are really enduringly interested in something eventually find that it's important, too -- and important to other people. Very few people can keep going their whole life doing something and feel like it's merely personally fascinating. Most people develop a sense of purpose in their work who are gritty.

Your idea is closely associated with education, partly because of your background, and how widely adopted the idea has been in that field. Do business leaders do a good job of measuring this concept?

I don’t think so. Partly because I don’t know how and I’m a scientist who studies it. I haven't met the company who has said to me 'we figured everything out, we absolutely know how to hire these gritty people.'

Grit, by definition, is sticking with things for a long time. How are you going to get at that in a 45-minute interview? It's not a trivial problem to solve. My best idea so far is to look for evidence of grit in something, even if it's unrelated to what you're hiring for. I know a lot of CEOs who are looking for three- to four-year varsity athletes -- not necessarily because these people are going to be doing pushups or spiking volleyballs in the workplace, but because they’re looking for that continuity, that person who was gritty about something.

How useful do you think it would be if businesses utilized your 'grit scale' -- a short questionnaire designed to measure those stamina levels -- in hiring? 

When I talk to employers about it I say don’t do that. For one thing, the scale is so fake-able. Any questionnaire like this is fake-able. The second reason is people’s standards really do differ. I was being interviewed by [Freakonomics co-author] Stephen Dubner, and he was taking the 'grit scale' with me, on the air. He got a more modest grit score than I would imagine. Like anyone else, part of his score reflects his standards. What does it really mean to be a hard worker? What does it mean to stick with things?

I think that is just a limitation of any questionnaire -- that we apply a frame of reference or standard. It's a well-known finding in psychology that when people are total beginners at a skill, they tend to overrate their skill level. They don’t know what they don't know. The more expert you are, the more critical you become. I don’t like self-reported questionnaires being used in any real high-stakes setting, one because of faking and two what's called the frame of reference bias.

But I do empathize with employers, because I'm an employer, too. I run a nonprofit, and I want to hire scientists and educators and I want gritty ones. But I just think the science isn’t there to say 'here’s the grit test' for high-stakes settings.

One critical review of your book said “grit” is really not that different from “conscientiousness,” a classic psychological trait. Another recent report questioned the originality of your idea and pointed to studies that question whether grit really predicts achievement and success. What’s your response?

I’d be lying if I didn’t say it bothered me. It's not that I have to be right about everything -- you stop being a scientist the moment you think you're right about everything.

In terms of "big five" conscientiousness [the idea from psychology research that you can divide up personality traits into five broad dimensions -- conscientiousness, agreeableness, neuroticism, openness to experience, extraversion], I also study that. If you go to my web site, I study grit, but I also study conscientiousness, and I study self control.

Each of these families can be then split into what are often called facets, and grit is arguably a facet of conscientiousness. But there are other parts of conscientiousness that are different: orderliness, punctuality, dependability. My claim is simply that this particular facet of the broader family of conscientiousness is especially predictive of challenging, meaningful accomplishment.

I don’t think grit is the only thing that predicts achievement. I'm particularly interested in high achievement over the long term [of] things that are meaningful and challenging. I don’t know any 16-year-olds for whom their standardized achievement tests are like their major passion, or they would feel it's a really meaningful, challenging goal.

When we talk about consistency of your interest, I think that the importance of that is not always easy to see when you're looking at people's standardized test scores. I do stand by my hypothesis, supported by some of my data. I'm sure science will accumulate more data, and things might need to be adjusted. People do great things when they are working with direction, not just determination. 

There's a chapter in the book titled "A Culture of Grit." How can leaders develop an environment that helps people be more persistent and passionate?

I’m of the school of thought that leaders do matter. I think that a strong leader is emulated -- not just imitated, but emulated. If you want a gritty culture, you should have a gritty leader, because they will set the pace for the rest of the organization.

I think one of the things that’s true about leadership is also true about parenting -- the best combination is to be challenging or tough but also supportive or loving. That expression 'tough love' actually has some scientific basis. People grow up best -- whether they’re in a company or a family -- when the people who are in charge are challenging. They often say things like 'this isn't good enough, I think we could do better.' At the same time, they are, in a really authentic way, unconditionally supportive.

Just before the call today I finished a board meeting for my nonprofit. And let me tell you, this board is challenging and supportive. There's nothing I told them that they didn’t give me 300 ways it could be better: 'Great -- but did you do this, this and this?' At the same time, I know they have my back, and they think this work is important. So one is to have a gritty leader who people can emulate, and create a culture that’s both demanding and supportive.

But how do you actually create that kind of culture? 

As [Seattle Seahawks head coach] Pete Carroll said to me, 'it’s not one thing, it’s a million things.' But there are some themes. One is language. It’s important to have a vocabulary that's used within that organization, and not to use synonyms. The second is rituals: you can ritualize things like working on your weaknesses -- at the Seahawks, they call it 'Tell the Truth Monday,' so it becomes a routine. On Mondays, we look at the things we're doing wrong. Tuesdays we do something different. I think that's helpful.

The third is that in group psychology, you basically create an identity. When people who work in a very strong culture identify themselves, they often use a noun form, such as a West Pointer. Or at KIPP, the charter school, you call yourself a KIPPster -- they will actually say out loud -- 'I’m not just a student, I’m a KIPPster.' When you break down what a culture is, it's reinforcing an identity of 'this is who we are. It's different from the way other people are, but you're in this group -- not their group.'

That Princeton professor who put this resume of his failures together made me think of your book. Would you like to see more leaders do that?

I think it's so brilliant, which is why I tweeted about it. In my own lab I send out all my rejection letters as soon as I get them. You get these really long, single-spaced rejection letters from journals saying how poorly written it was, how uninteresting it was, how methodologically flawed it was -- it goes on and on and on in excruciating detail. I don’t want to shame people, but when it’s my own work, I always send it out to my lab because I want them to see.

Being strong enough to show people when you're weak -- it’s a goal of mine, and it's also something I noted about a lot of the gritty individuals whom I profiled.

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