An international study of reading literacy among fourth graders has found that students in the United States scored above the average for the 40 nations covered but trailed their counterparts in a dozen nations and several Canadian provinces.

The study, released this morning, also found that in all of the nations surveyed, girls outscored boys, and fewer children reported deriving enjoyment from reading than was the case when the international assessments were last given, five years earlier.

The study was conducted by researchers at Boston College on behalf of the International Association for the Evaluation of Educational Achievement. Each of the 40 nations involved in the study evaluated about 4,000 students in 150 schools, with those in the Southern Hemisphere beginning their data collection in October 2005 and those in the Northern Hemisphere beginning in March 2006.

The highest scores were posted by Russia, followed by Hong Kong, the Canadian province of Alberta, and Singapore. The other nations posting substantially higher scores than the United States included Bulgaria, Germany, Hungary, Italy, Luxembourg, and Sweden.

The researchers examined various factors thought to influence reading achievement, extensively questioning parents and caregivers. They found that the strongest readers came from nations where reading was stressed in the home at an early age, and that those students who spent the most time in early-childhood education generally had the highest scores. —Peter Schmidt