Grit has been touted as the great equaliser: disadvantaged pupils who learn to try, try and try again, its proponents say, are more likely to succeed.

But a new study has found that pupils’ grittiness is no guarantee either of academic performance or of success.

Instead, academics from Iowa State University state that improving pupils’ grittiness has less effect on their academic outcomes than teaching them study skills or ensuring high attendance levels.

The Iowa researchers conducted a review of 73 existing studies on grit, involving 66,807 individuals. Their paper, published in the Journal of Personality and Social Psychology, has found that improving pupils’ grit - defined as a combination of passion and perseverance - is not a guaranteed way to ensure improvement in their results.

Grit - which was identified and popularised by University of Pennsylvania psychologist Angela Duckworth - has been promoted by the Department for Education in this country as a way to ensure that all children, regardless of background, perform well at school.

In December 2014, Nicky Morgan, then education secretary, allocated £3.5 million to be spent on classes and extracurricular activities that built grit and resilience. And, in April this year, she reiterated her focus.

But the Iowa academics insist that grit alone is not enough to determine success. High levels of grit, they say, need to be “accompanied by the general potential or ability to succeed in a domain”.

For example, they say, grit is unlikely to make much difference to army cadets who lack the physical ability to pass a military academy’s physical exam, or to students who persist on revising in a way that is not working for them.

Equally, the researchers add, high levels of grit can become dysfunctional, “if they increase the likelihood that an individual persists too long in attempting to solve a problem that is particularly difficult, rather than spending their time on other, more solvable problems”.

Alternatively, someone with particularly high levels of grit may be unwilling to ask for help, even when it is necessary.

James Arthur, director of the University of Birmingham’s Jubilee Centre for Character and Virtues, also has misgivings. “Grit’s like a muscle that does things,” he said. “It doesn’t have any moral context to it.

“I think some of our government think it’s a good thing, and I’m trying to tell them that it’s not as good as they think. You can use grit for good purposes or for bad purposes. People who are members of criminal gangs have a lot of resilience and a lot of grit.

“It has to be seen within a broader moral compass. If it’s not within that moral framework, it can become very dangerous.”

Kristján Kristjánsson, deputy director of the Jubilee Centre, said that grit could be taken to undesirable extremes. “You can be too gritty,” he said. “The anorexic girl is too gritty.”

The Iowa State study says that, even when grit is developed in moderation, its effect on academic performance is often limited. “Study habits and skills…report correlations with academic performance and retention that are more than twice as big as those observed for overall grit,” the report said.

The study concludes that grit’s reputation as a predictor of academic success is therefore undeserved: grit is simply a repackaging of personality attributes - such as conscientiousness, self-regulation and self-efficacy - that psychologists have already been studying for decades.

Professor Kristjánsson agreed. “It may well be that ‘grit’ is a catchy term that appeals more to parents and teachers than old, boring psychological terms,” he said. “Angela Duckworth is a big star in psychology. She seems to have touched a chord.”

But Sir Kevan Collins, chief executive of the Education Endowment Foundation, believes that this is no reason to rule out the role of grit altogether. “The absence of evidence doesn’t mean that it doesn’t exist,” he said. “There’s promise, and there have been very few trials in England. We have to keep looking.

“‘Grit’ is a new word. What does it actually mean? Just because we haven’t found strong causal links with attainment, doesn’t mean we should stop looking for them.”

For more on grit and a closer look at character education, see our special issue on 16 September