A study by Cambridge University suggests an extra hour of exposure to the internet, television or a video game each day, during year 10, is linked to a drop in GCSE performance.
The activities of 845 students from Suffolk and Cambridgeshire schools, aged 14 years old, had their activities recorded by the researchers, who then analysed their GCSE results when they were 16 years old.
They also had their weight and height recorded, and were required to wear a physical activity monitor for five days and one weekend.
Students who had spent an extra hour each day looking at a screen saw a drop in their GCSE performance equivalent to two grades overall.
The students had to answer a questionnaire about the amount of time they spent doing homework, exercise, watching television, playing video games, reading for pleasure and going online for non-homework use.
The researchers then correlated the information with the GCSE results obtained the next year, and found that students who spent an extra hour on homework or reading achieved better grades than their peers. Time spent doing physical activities was found to have no impact on academic performance.
An additional hour of screen-time every day was linked to 9.3 fewer points obtained in GCSE exams, which is the equivalent of dropping one grade in two subjects.
“We followed these students over time so we can be relatively confident of our results and we can cautiously infer that TV viewing may lead to lower GCSE results, but we certainly can’t be certain,” said Dr Kirsten Corder, the lead author.
“Further research is needed to confirm this effect conclusively, but parents who are concerned about their child’s GCSE grade might consider limiting his or her screen time.”