Girls do better in STEM subjects when exams are longer, because they can hold their concentration better than boys, a new study has found.

If tests are made longer girls could perform better in science, technology, engineering and maths subjects, potentially encouraging more to take up the subjects, the research suggests.

It’s estimated only 13 percent of the overall STEM workforce in the UK are women, and just 15 percent of engineering graduates are female.

“Promoting gender equality in STEM course enrolment and career choice is on the policy agenda of many governments worldwide. Gender-balanced test scores might help to achieve this objective,” Pau Balart and Matthijs Oosterveen, of Universitat de les Illes Balears, Palma, Spain, wrote.

“Gender differences in test performance in math and science have generally been perceived as a female weakness. Our findings could serve as a counterbalance to the gender stereotypes shaped by this perception.”

Using data from the international standardised test, PISA, from 74 countries the researchers analysed the exam results of 15-year-old’s in both verbal and reading and maths and science tests.

Their study, published in the journal Nature Communications, supported previous findings that girls outperformed boys on verbal reading tests, while boys outperformed girls on maths and science tests.