Media playback is unsupported on your device Media caption The research involved more than 600 children 14 to 16 year-olds

Children who play video games twice a day are less likely to achieve five good GCSE grades, a study suggests.

The National Children's Bureau Northern Ireland research involved more than 600 14 to 16-year-olds from 2012-14.

It found 41% of children who used portable gaming devices at least twice a day achieved at least five GCSE A* to C grades, compared with 77% of those who used them less than once a week.

The research does not establish why this might be the case.

Internet safety

The report, ICT and Me, is the first long-term study in Northern Ireland into how a child's use of information and communication technology (ICT) impacts on GCSE attainment.

Although 81% of the young people in the study reported using social media daily, many for several hours, it found no link between social media use and exam performance.

The report says there is "no statistically significant association between pupils' intensity of participating in social networking activities and educational attainment at GCSE level".

Its other main findings include:

Young people spend a significant time online each day, with four in 10 young people spending four hours or more online in the year they take GCSEs

The bulk of this time is spent on recreational activities with many young people (43%) spending less than an hour each day using a computer for homework

Pupils who spent about three hours every day using a computer to do homework achieved the best exam results, with 79% achieving five A* to C grades in their GCSEs

'Too much or too little use of ICT for homework also had an effect. Those who spent no time using a computer for homework or who spent more than three hours using a computer for homework, did worse than average with only 57% getting five A* to C grades'

There was no statistically significant link between mobile phone or tablet use and attainment at GCSE level

While internet safety was a particular concern for teachers and parents, pupils themselves were more comfortable with their online safety with almost three-quarters (72%) saying they felt safe online

While the report recommends the introduction of a targeted scheme by government to ensure all young people have access to a computer or laptop at home, it also recommends that parents or carers limit the amount of time their child uses a games console.

Setting homework

It also recommends that additional research is undertaken to establish why prolific gamers do less well at school.

Celine McStravick, the director of the National Children's Bureau Northern Ireland, said: "Our research shows that using a computer for homework can help pupils consolidate learning and do better in exams.

"So, schools should be regularly setting homework that requires the use of a computer and the internet.

"Similarly, we need parents and carers to step in and limit excessive amounts of time spent gaming."

The research was funded by the Office of the First Minister and Deputy First Minister, a department of Northern Ireland's ruling executive.

Of the 611 14 to 16-year-olds tracked at 13 post-primary schools in Northern Ireland from 2012-14, 65.5% achieved at least five GCSE grades at A* to C.