Bigger class sizes make students more resilient.

That was just one of several eyebrow-raising claims that Ontario Education Minister Lisa Thompson made during an interview last week. Her comments quickly provoked a deluge of criticism from many members of the public, educators and the opposition parties.

In an interview with CBC Radio's Metro Morning, Thompson said that businesses and post-secondary educators relayed to her during recent consultations that students are "lacking coping skills and they're lacking resiliency.

"By increasing class sizes in high school, we're preparing them for the reality of post-secondary as well as the world of work."

Thompson was defending the government's recent decision to increase high school class sizes in the province from 22 students to 28. Since that's a board-wide average, some classes — especially important pre-requisites — could swell to as many as 38 or 40 students, educators have warned.

You can listen to the full interview below:

Grades 4 to 8 will see a more moderate average increase of one student per class, while earlier grades will remain the same.

So does the government's plan make sense? CBC Toronto took a deeper look.

'Resilience' is complicated

The impact of class size on students has been debated for decades, both in the halls of academia and among policymakers. Numerous studies, conducted worldwide, have produced varied results.

Generally, there is scholarly consensus that smaller class sizes improve academic achievement, particularly among vulnerable student populations. But the extent, scope and ultimate value of those improvements is limited, and the benefits diminish as students get older. And it is far from a magic bullet.

In her interview, Thompson said: "The biggest factor in student success is actually how effective the teacher is" — and there is research that supports this assertion when it comes to high school-aged children.

Charles Pascal, a professor at the Ontario Institute for Studies in Education, former deputy minister of education and an architect of Ontario's early education approach, told the Globe and Mail in January that "in high school and university, pedagogy trumps class size."

However, on Twitter, Pascal has criticized Thompson's statements, calling the increased class size the "opposite of what is needed."

Listen to Ottawa Morning's education columnist discuss class sizes below:

While high school students may be able to handle larger classes, research shows the same cannot be said for primary students. That's likely why the Progressive Conservatives opted not to remove class size caps for kindergarten through Grade 3, a move that certainly would have ignited even sharper backlash.

It's also important to note that academic success and resilience are not one and the same. Two prominent Australian educators define resilience as "the ability to cope or 'bounce back' after encountering negative events, difficult situations, challenges or adversity and to return to almost the same level of emotional wellbeing. It is also the capacity to respond adaptively to difficult circumstances and still thrive."

Indeed, building resiliency in children is increasingly included as a goal in curriculums. The concept has gained momentum in many U.S. states, for example, that cater to students coming from adverse circumstances.

But there is little evidence that bigger classes help students become more resilient. In fact, the Centre on the Developing Child at Harvard University says that "the single most common factor for children who develop resilience is at least one stable and committed relationship with a supportive parent, caregiver, or other adult."

That includes teachers.

If, as many educators say, large class sizes make it harder to form constructive student-teacher bonds, Ontario's current plan could be counter-productive.

Aligning with other provinces?

As part of her defence of bigger high school class sizes, Thompson asserted that increasing the average class size to 28 would "better align ourselves with other jurisdictions."

"Ontario, over the last number of years, has had an incredibly low teacher-to-pupil ratio," Thompson said in an interview with CBC's Power & Politics after the new policy was announced.

Ontario's average high school class size requirement of 22 has been in place for more than six years, and is indeed lower than other provinces.

The target was reached after the Liberal government, beginning with former premier Dalton McGuinty's election in 2003, began pouring hundreds of millions of dollars into reducing class sizes across all grades.

Boosting the average secondary class size to 28 would still see Ontario rank on the lower end of the spectrum.

Making direct comparisons with other provinces is difficult, because different jurisdictions use different standards — some have hard caps, some have targets, while others use averages.

Quebec, for example, has a cap of 32. Alberta doesn't have hard caps, but maintains a target of 27. For many years B.C. maintained a limit of 30, however now limits are negotiated at the local level through collective agreements.

Saskatchewan has no class size limits at all, while in most of Manitoba the maximum class size is 35. Requirements are also generally higher in the Maritimes, with a limit of 30 for Grade 10 to 12 in Nova Scotia and P.E.I. and 29 in New Brunswick.

Meanwhile, private schools in Ontario tend to have significantly smaller average class sizes, with many in the mid to high teens.

Is this really what educators want?

In her interview with Metro Morning, Thompson said teachers told her during consultations that between 26 and 28 students is the "ideal" range for facilitating group work and fostering a "team environment" in high school classrooms.

A significant body of international research has grappled with the question of the ideal class size. But there are so many factors at play in any given jurisdiction that coming to any meaningful conclusion is widely regarded as impossible.

For its part, the Ontario government says that the consultation process itself involved 72,000 "engagements."

"This is the total of completed online surveys, open submission forms, email submissions and telephone town hall participants," a spokesperson for the Ministry of Education said in an email.

"For the email submissions, we received feedback from trustee associations, teacher and education worker federations and unions, parent groups, non-profit organizations and post-secondary institutions."

CBC Toronto followed up, asking the ministry who or what groups provided feedback on the resiliency of students and advocated for larger class sizes, but did not receive a response.

Unions representing both elementary and high school teachers have been fiercely critical of the choice to increase class sizes in intermediate and high school grades — warning teachers will face unsustainable workloads and have less time to build constructive relationships with students, especially those who may require extra help.

Thompson has repeatedly promised that there will be no "involuntary" job losses among teachers as a result of the changes.

The Ontario Secondary School Teachers' Federation, however, says that as many as 20 per cent of high school teachers working in the publicly funded system could be affected. Meanwhile, the Toronto District School Board said in a memo that some 800 of its high school teachers could lose their jobs.

Listen to the chair of the TDSB discuss job losses below:

The government is expected to shed those jobs through retirements and resignations, however Thompson told Power & Politics the province is still "working through that with our school boards."

"It's too early to say what that will look like on a board-to-board basis."

Thompson has also not revealed how much money the government thinks it will save by increasing some class sizes.

Many supporters of smaller classes say any short-term savings will be far outweighed by the costs of remedial supports down the road, such as social services.