A Mathematics teaching craze known as “Building Thinking Classrooms” (BTC) is now sweeping across North American K-12 education. With post-pandemic student math scores languishing and senior administrators scrambling for a quick fix, BTC has quickly taken over classrooms with its small group engagement activities and wall-mounted strip whiteboards known as “vertical learning spaces.” It’s also acquired a new and rather cheeky moniker on social media—#sinkingclassrooms. 

Since its founder, Simon Fraser University education professor Peter Liljedahl, spoke at the Ontario English Catholic Teachers’ Association’s Toronto conference on May 2, 2015, BTC has expanded from its British Columbia origins and spread to proliferate classrooms around the world. It easily captured school system leaders and was seeded in local professional development sessions for school administrators and curriculum consultants. It has great appeal to principals and teachers, often with little mathematics background, steeped in “progressive” teaching methods attempting to hook kids and overcome their math anxieties.

However, university mathematics professors, specialist teachers, and engaged parents are beginning to raise serious objections to Liljedahl’s math teaching philosophy, its limited research basis, and its visible impact on students already struggling in mathematics. While Liljedahl’s approach is purportedly backed up by research, that claim is now attracting more critical scrutiny. Leading Canadian mathematics expert Dr. Anna Stokke of the University of Winnipeg is very skeptical about its research basis and is seriously questioning its widespread use in classrooms. 

The whole approach is rooted in progressive teaching philosophy and espouses a popular and largely discredited strategy known as “minimally guided classroom instruction.” Most lessons begin with students assigned tasks in groups of two to three or four and asked to collaborate on problem-solving. 

Here’s how it works. First, the groups are randomly selected, purportedly to promote connection and different thinking. With a minimum of direct instruction, the lesson revolves around vertical learning, random groupings, and a wide variety of curricular and non-curricular thinking tasks. Essentially, every day in math class, students are mostly placed in small groups and left alone to figure out the answers. 

Liljedahl’s book, Building Thinking Classrooms, is described by Nova Scotia math teachers as “the bible” and the walls of many math classrooms are covered in “vertical learning spaces” (whiteboards). A patented commercial product, known as “wipebooks,” is tied in with the consultant’s work and, in PD sessions, they are freely distributed to teachers, especially in schools affiliated with the Halifax Regional Centre for Education

American mathematics educator Michael Pershan, author of Teaching Mathematics with Examples, was one of the first to raise objections. The founder makes “big claims” that the approach is research-based based on four academic articles, but, in his view, “the evidence is weak.” Surveying his supporting studies, Pershan found that “it doesn’t support big generalizations.” 

A few examples will suffice: Liljedahl’s research measures engagement but not learning; it focuses on only two aspects in engagement with vertical whiteboards and homework; it counts teacher uptake as engagement; and it is entirely based upon older students with some math background. Most critical of all, there’s no indication of how the test groups of students were selected or any explanation of how his percentages are derived in his reports. 

The BTC philosophy has some appeal because it creates a buzz of activity. It gained a foothold because its founder is engaging and it works best with teachers who have prior knowledge of mathematics. Regular students struggling in the subject, left to fend for themselves, tend to get lost and either tune out or act out in class. That’s the dominant view of several teachers who spoke with me but, sad to say, insisted on remaining anonymous for fear of repercussions.  

“Creative thinking” is the buzzword of our time, and anything attached to it attracts senior administrators looking to make an impact. Right across Canada a sizable proportion of the teachers in math classrooms have only a smattering of mathematics background or are teaching “out of field.” Student engagement is their priority and BTC fills that bill, even if it doesn’t improve students’ mastery of mathematics nor deepen problem-solving skills. 

School leaders know their audience. “Nobody reads the papers,” Pershan points out. “Very few people care about getting this right. And yet, apparently, almost everybody cares a great deal about the perception that some new thing is rooted in research. It opens doors, hearts, and minds.” It also generates speaking tours, substantial consulting fees, and sucks-up time and resources better spent actually teaching kids how to do math and get the correct answers.  

Engaged parents exposed to “Building Thinking Skills” promotional meetings are beginning to raise questions that are unlikely to go away. Liljedahl claims to be building “thinking classrooms” (BTC, 2016a, p. 364), but parents are getting a one-sided sales pitch, and critical questions are being brushed aside. It did not go over well in Berkeley Heights public schools, where a November 2022 parent survey revealed that the vast majority of parents and students found BTC ineffective and petitioned the school district to suspend the program.  

One razor-sharp Greater New York City parent, Virginie Delwart, active with Berkley Heights Community Watch, claimed that many students were struggling to master math in the program and it was dividing both her family and the community. Too many honours students were bombing their assessments, and weak students with learning challenges were completely lost. 

What’s my take on the latest craze? The fix is in and, judging from the North American social media reaction, BTC is saddled with the unfortunate label of “sinking classrooms.” It’s unlikely to improve student math scores or raise achievement.          

Pierre Poilievre declared early last week that his party supported limiting child access to online porn. The news was breathlessly reported, the X analysis began, and it only took about 48 hours for the debate to shift from differences in principles and worldviews into a “well, actually” scuffle over technocratic implementation challenges.

Why was that?

As libertarians (of all partisan stripes) took to social media to mock Poilievre on principled grounds, I suspect that in making their arguments, they found their own messaging rather unpalatable, or at least they realized most Canadians would. You can just imagine how the thought process went. “HA!”, they thought to themselves. “Mr. Freedom himself isn’t so interested in all those freedoms, is he??” (So far so good). “I guess his consistent worldview isn’t so consistent after all!” (How embarrassing for him!) “I guess he doesn’t feel strongly enough about completely unfettered access to highly exploitative and disturbing online content for kids, does he??” (OK, maybe this part needs some spin.)

Because of course children shouldn’t have easy access to porn on the handheld devices they carry with them all day, every day. The very notion is so absurd that the only way to defend it is to change the nature of the argument. Given the necessary implication of a freedom-of-expression-based argument (that the adult right to expression outweighs a duty to protect children), I would probably pivot away from that path of argumentation quickly too. And to be fair, the technical policy arguments against age-gating are far stronger. Poilievre sought to address one of those arguments quickly, his office clarifying that his party would not support a digital ID. Still, implementation would be difficult. We’re not used to regulating the internet and writing policy to address external harms caused by new technology has never been easy. Wise policymakers will no doubt recommend an approach that allows for adjustments as legislation and regulation are tested by real-world applications. 

Age verification will be tricky to implement, and any approach will come with risks. But let’s be clear about what those risks are. They’re not about a threat to freedom of expression. The libertarians put that matter to bed when they realized that arguing a porn star’s (or, perhaps more truthfully, a porn profiteer’s) right to self-expression supersedes our duty to children was a non-starter. For the implementation-is-hard argument, the risks are to the porn companies, and the troublesome red tape they’ll encounter (pour one out for Pornhub, I guess), and, more seriously, to the privacy of adults viewing porn online. Any time adults are required to provide proof of identity in a digital environment, there’s a risk of a data breach. It’s a real problem. But it’s a problem that affects many of our online interactions. Yes, it will be difficult to confirm age.

And of course, gathering personal data carries the risk of a data breach. But as our country increasingly operates online, this is already true. Whether we book plane tickets and provide our passport numbers, log on for some i-gaming and prove our age, or go online shopping and share our credit card numbers, we share data online all the time, taking the risk that our identity or payments might be compromised, and expecting the private sector and government to develop more sophisticated solutions to protect against that as time goes on.

“What about the parents?” you might say. “Why should I sacrifice my right to privacy and risk a data breach just because parents can’t keep their kids off porn sites?” I would direct your attention to the evolving policy matter of smartphones in schools. Some technologically powerful cultural trends are simply too potent for individual parents to push back against on their own. I won’t rehash the harms that early, frequent access to porn has on developing minds at great length, but they are plentiful, and it’s probably fair to say we haven’t yet measured the extent of it given that Gen Z is the first generation to carry social media on their phones, in their pockets, from childhood. Given the knowledge we do have, I think it’s unacceptable for policymakers to simply turn away, washing their hands of the issue and hoping kids come out relatively unscathed.

In high-functioning societies, we trade off rights, privileges, and duties all the time in public policy-making. “Ordered liberty” often requires that the strong in society give up some freedoms in order for us to collectively protect the weak. So, the question becomes, do you think an adult’s absolute right to guaranteed privacy online in every circumstance outweighs our duty to protect children from harmful content? I say no. Assuming we make every effort to protect adult privacy and are thoughtful about the policy design required to do so, we ought to prioritize our duty to protect children from harm. I suspect most Canadians agree with me.