Canadian students rank among the best of their international peers when it comes to math, science and reading — but Manitoba's students are pulling that average down.

The results of the most recent Program for International Student Assessment (PISA) show Manitoba ranks second last in Canada (just ahead of Saskatchewan) in both science and reading, and is third last in math.

The PISA assessment — conducted by member countries of the Organization for Economic Co-operation and Development (OECD) — was a two-hour computer-based test administered to 15-year-old students during regular school hours in April and May 2015.

The exam showed Manitoba students are roughly one year behind in reading and science and more than half a year behind in math compared to the top-ranking provinces, said Jeff Mo, analyst at the OECD.

"​Students in Alberta, British Columbia or Ontario are much higher in the socioeconomic scale than students from Manitoba and Saskatchewan," said Mo.

"As a result you do see that reflected in Manitoban students' performance."

Focus on science, reading, math

PISA, which is done every three years, evaluates education systems worldwide by testing 15-year-olds in key subjects. The primary focus of PISA 2015 was scientific literacy, with a minor spotlight on math and reading.

Some 540,000 students across 72 countries or cities, including approximately 20,000 Canadians, took part. The full report, together with country analyses, summaries and data, is available on the OECD website.

Canada released its own companion report, Measuring Up: Canadian Results of the OECD PISA Study.

Internationally, Singapore outperformed the rest of the world while Japan, Estonia, Finland and Canada were among the top countries.

According to the results, more than one in five students falls short of baseline proficiency in science. Only in Canada, Estonia, Finland, Hong Kong (China), Japan, Macao (China), Singapore and Vietnam do at least nine out of 10 15-year-old students master the basics that every student should know before leaving school.

At the provincial level in Canada, students in Quebec, Alberta and British Columbia performed above the Canadian average (528) in overall science, with scores of 537, 541, and 539, respectively. Only Singapore (556) had higher achievement than these three jurisdictions.

Students in Manitoba and Saskatchewan were well below the Canadian average at 499 and 496, respectively. Those scores, however, were still higher than the OECD average of 493.

Manitoba students' performance has declined in every PISA testing year since 2006, when they scored 523. They followed that up with scores of 506 (2009) and 503 (2012).

On average, Canadian students performed well in reading and mathematics, with an average score of 527 in reading and 516 in mathematics, above the OECD average of 493 and 490, respectively.

In reading, Manitoba students scored 498, which is up two points from the scores in 2009 and 2012. Saskatchewan was last at 496.

In math, Manitoba students scored a 489, just ahead of Newfoundland and Labrador (486) and dead-last Saskatchewan (484).

Teachers' society pans PISA

Manitoba Teachers' Society president Norm Gould said he puts little stock into PISA, the OECD and their results.

"PISA is a 'product' of the Organization for Economic Cooperation and Development. The tests themselves are a business and economic think tank's concept of what's important in education," he said in a statement released in response to the results.

"If we want to know how Manitoba students are performing, ask their teachers. Manitoba's teachers are some of the most highly trained in the country and use a variety of assessment and evaluation techniques every day in classrooms all across the province."

Gould said the province should consider why it participates in the test and what benefits are derived from it.

"Highly recognized academics from all over the world, including those from countries that perform well on these tests, have criticized the motives behind and usefulness of PISA rankings," he said.

Anna Stokke, math professor at the University of Winnipeg, said PISA shows Manitoban students are behind and will have trouble competing with other students in Canada and elsewhere in the world.

"We don't have as many students performing in the highest level as we should," Stokee said.

Manitoba could start to correct the problem by implementing more standardized tests provincially to catch problems early.

"I think we do need to see some Manitoba-made tests," Stokke said.

"So that we can learn what's going on...and get some feedback on how they're doing before we go to the international tests."