By Holly Yettick, Education Week
While U.S. students often catch flak for their performance on large-scale international assessments, they may be approaching world dominance on one such indicator: sleepiness.
In both the Trends in International Mathematics and Science Study and the Progress in International Reading Literacy Study, the percentage of U.S. pupils enrolled in classrooms in which teachers report that student sleepiness limits instruction "some" or "a lot" in 4th grade reading and 4th and 8th grade math andscience has consistently exceeded 70 percent. Internationally, overall averages for sleepiness range from 46 percent to 58 percent, depending on the grade level and the subject. (Eighth grade science classes were the "sleepiest.")
What does this all mean? It is difficult to say. In 2011, the journal Sleep Medicinepublished a meta-analysis of 41 studies that found that, at least in adolescence, students in Asian nations went to bed latest on school nights, resulting in the world's highest rates of daytime sleepiness. But a quick glance at the TIMSS and PIRLS charts suggests that the United States generally has higher percentages of students enrolled in classes in which teachers reported that sleepiness limited instruction. Although some Asian nations and jurisdictions reported relatively high rates in certain subjects or grade levels, others (especially Japan) are generally below the international average.
By contrast, U.S. rates range from 73 percent in science and 4th grade math to 85 percent in 8th grade science. Countries and jurisdictions with similar rates in at least some grade levels or subjects included Australia, Taiwan, Finland, France, Hong Kong, New Zealand, Saudi Arabia, and Turkey. However, because of the way the data were collected, TIMSS and PIRLS could not say where, precisely, the United States ranked in the world.
"What we can say is that greater percentages of students in the United States, in comparison to other countries, have teachers that report their instruction is limited due to students' lack of sleep," said Chad Minnich, a spokesman for the TIMSS & PIRLS International Study Center at Boston College. "Further, our data show that when instruction is limited due to students' lack of sleep, that achievement in mathematics, science, and reading is lower."
However, Iris C. Rotberg, a research professor of education policy at George Washington University in Washington, says that valid conclusions about students' sleepiness cannot be drawn from teachers' responses to a questionnaire item asking to what extent their instruction was limited by students suffering from a lack of sleep.
"Further, because of the basic sampling and measurement flaws in international test-score comparisons generally, the factors contributing to test-score rankings cannot be accurately identified," Ms. Rotberg said.
But in a commentary published last month in the journal Teachers College Record, Meilan Zhang, an assistant professor of educational technology at the University of Texas at El Paso, argued that "[r]esearchers, policymakers, teachers, health-care practitioners, parents, and students" should take notice of the TIMSS and PIRLS findings.
"Improving student sleep deserves more attention than is currently received in public discourse and national agendas for education," she wrote. "It is likely that when the sleepiness rankings of U.S. students go down, their science, mathematics, and reading score rankings will move up in the next TIMSS and PIRLS."
Ms. Zhang's theory is that U.S. students are sleepy in school because they spend too much time texting, playing video games, watching TV, and using media in other ways.
"Heavy media use interferes with sleep by reducing sleep duration, making it harder to fall asleep, and lowering sleep quality," she wrote, citing a 2011 research review in the journal, Sleep Medicine.
But the relationship between youth media use and sleep is not so simple, said Michael Gradisar, who coauthored both that review and the Sleep Medicine meta-analysis.
"Technology use is the new culprit when trying to answer 'Why are school-age children sleeping less?'" said Mr. Gradisar, an associate professor of psychology at Flinders University in Adelaide, Australia.
There may be safe limits to technology use, Mr. Gradisar stated. For instance, recent research results indicate that using a bright screen for an hour before bed or even playing violent video games for less than that will not necessarily interfere with teenagers' sleep, he wrote.
But longer periods of usage can be harmful to sleep, Mr. Gradisar added. Rather than delay school start times, he said, a first step should be educating parents about limiting the hours their children are using technology before bed, and enforcing a consistent bedtime.
Early school start times are also commonly blamed for student sleepiness, especially for adolescents. Secondary schools around the nation and the world have been delaying start times, often with positive results.
Mr. Minnich of the TIMSS and PIRLS center hesitated to "attribute causality or apportion blame to any particular factor." But he did speculate that cost-saving measures to consolidate bus routes might help explain U.S. students' sleepiness.
"For those children who board the bus first, they must get up earlier, may end up dozing en route to school, and may end up arriving at school sleepy," he said.