Reading ability among children aged 9-10 has fallen in the US, Canada, France and several other developed countries, according to a comparative study of 50 countries published Tuesday.
Ten countries fared worse, compared with five years ago, in the 2016 PIRLS assessment of pupils in their fourth year of schooling -- namely Belgium, Canada, Denmark, France, Iran, Israel, Malta, New Zealand, Portugal and the US.
Eighteen, including England, Russia and Qatar made improvements.
Russia and Singapore topped the boards with 581 and 576 points respectively in the study of 319,000 children, who were assessed on their ability to understand literary and informational texts.
Egypt scored 330 points, while South Africa finished at the bottom with 320 points.
Girls outperformed boys in 48 countries, with an average difference of 19 points, and matched their reading abilities in two -- Portugal and Macau.
Boys' reading skills particularly lagged those of girls in mostly Muslim countries such as Saudi Arabia, Oman and Iran, but the gap was also large in secular South Africa.
The study, conducted by the Netherlands-based IEA international education charity, is the fourth of its kind since 2001.
It contains comparative information on time and resources devoted to teaching reading but does not draw conclusions, or make suggestions, about how countries could improve.
Other findings include:
-- Reading standards among French fourth-graders -- who scored 511 points to take 34th place out of 50, behind Kazakhstan -- have fallen steadily since 2001.
-- In South Africa, which was the only African country to participate, girls pulled up six points between 2011 and 2016, while boys dropped 12 points.
-- In Iran, reading levels among both sexes shot up between 2006 and 2011 only to plummet in the past five years. The boys' score fell 41 points between 2011 and 2016, compared with 15 points for the girls.
-- In the US, 98 percent of the students had a library in their classroom, compared to just 14 percent in Egypt.