**by Marilyn Achiron****Editor, Education and Skills Directorate**

Got a minute? How about 218 of them? That’s the average amount of time students in OECD countries spend in mathematics class each week (although to some, it feels like an eternity). Spare a thought, though, for students in Chile: they spend about twice that amount of time (400 minutes, or 6 hours and 40 minutes) each week in maths class. But who’s counting?

Actually, PISA is. PISA 2012 asked students to report how much time they spend in their mathematics, reading and science classes – the three core subjects PISA assesses. PISA wanted to find out whether students are spending more or less time in class than their counterparts did a decade ago, and whether there is any relationship to the amount of time spent in class and student performance.

As this month’s PISA in Focus reports, across OECD countries, 15-year-old students spent an average of 13 minutes more per week in mathematics classes in 2012 than they did in 2003. PISA found that mathematics classes in all types of schools – public and private, advantaged and disadvantaged, lower and upper secondary, urban and rural – were longer in 2012 than they were in 2003. Students in Canada and Portugal spent 1.5 hours more per week in maths class than their counterparts did in 2003, while students in Norway, Spain and the United States spent at least half an hour more.

PISA also found that students in schools where more time is spent teaching mathematics tend to perform better in the PISA mathematics test. In fact, the net pay-off for mathematics performance from attending one of these schools is an average of 12 score points (the equivalent of roughly a trimester of schooling) per extra hour of mathematics instruction per week.

But if more is better in this case, then socio-economically disadvantaged students are missing out. This is particularly true for science lessons. Across OECD countries, students in disadvantaged schools spend 36 minutes less in science class than their peers in more advantaged schools. And in Argentina, Japan and Chinese Taipei, students in disadvantaged schools spend at least 76 minutes less in maths classes than students in advantaged schools, on average.

Of course, time is also measured in quality; and if those extra minutes in maths class are not filled with engaging curricula taught by innovative, supportive and motivated teachers, then more time is just a waste of time.

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