9 . Teenagers who spend more than six hours online on school days are more likely to be lonely and skip school, according to an international study.

The study examined the home Internet use, well-being (幸福) and behavior of 296,000 15-year-olds in 41 countries. More than one in four spent more than four hours per day online outside of school. The study found lower levels of well-being among students who spent six hours per day online. They were twice as likely as teenagers spending one and two hours per day online to report that they felt lonely at school. These “extreme Internet users” were also especially at the risk of “behaving in problematic ways at school, such as arriving late or skipping class.”

The report said, “Lower levels of engagement (亲密关系) with school may be connected to less sense of belonging at school. It is also possible that skipping class and arriving late for school are the consequence of lack of sleep among extreme Internet users.” It adds, “Parents, school and health professionals can work together to watch and plan children's use of new media.”

The study also found that countries that invest (投资) heavily in Information and Communication Technology (ICT) in schools have seen no “considerable” difference in 15-year-old’s achievement in reading, math or science tests. The study results suggest “limited” use of computers at school “may be better” than not using them at all. However, students who use computers “very frequently” at school “do a lot worse in most learning outcomes”. The report says, “In the end, technology can strengthen great teaching, but great technology cannot replace poor teaching.”