"All of them are working," she says. "Some in small groups, some individually, some in pairs, but each one is working with their learning guide and knows exactly what they are doing."
The guides are detailed textbooks that outline the Escuela Nueva curriculum for students and teachers, and embody the knowledge acquired by practitioners over four decades.
"The pupils can explain to you what they are doing, how they are learning. The teacher is going from group to group, giving them feedback during the learning process," Colbert says. "The teacher is spending more time with slow learners, asking questions. This is the role a teacher should play: an activator, facilitator, orientator - not just a teacher transmitting instructions."
Students are also expected to make a wider contribution. In the school they take seats on councils and committees; in the community they disseminate learning to their families. "Children become agents of change because they apply knowledge. Everything they learn, they apply with their parents," Colbert continues. "Every day. That's the way all the lessons are designed. Instead of traditional homework, they bring things to their homes [for the whole family]."
While many educationalists believe technology holds the secret to improving standards, Colbert is more circumspect. "We have to make sure [technology] doesn't introduce noise to the way children are learning and interacting," she says. "In secondary schools, we've introduced virtual links to the printed material, so in any lesson [students] can also have a virtual resource.But I'm very cautious about introducing a lot of new gadgets.
"We have to be careful we don't limit the interactions of children. They're already talking regularly among themselves [in the classroom], so we have to see what can be adapted to support what they are doing, but also keeping the costs down. We're introducing virtual resources, but cautiously."
Today's Escuela Nueva schools look very different from the rural, multi-grade primaries Colbert visited on her return to Colombia in the 1970s. "The public schools had low results, high dropouts, low retention, high repetition rates and low teacher morale," she says. The pedagogy was stuck in "the past century" and focused heavily on rote learning, and teaching materials were almost non-existent thanks to low funding levels. "These schools were invisible to educational planners and teachers' colleges. There were so many difficulties that it was like a failed company. Nothing worked."
Colbert wasn't the only person to realise that drastic change was needed. A United Nations Educational, Scientific and Cultural Organisation (Unesco) team was already working in the country on a "unitary school" project, but the high demands their approach placed on teachers had provoked the ire of education unions. Colbert sensed an opportunity.
"We needed a new learning paradigm. With all these constraints we had, this was a great opportunity to rethink the whole thing, because nothing worked," she explains. "It was an opportunity to reinvent everything: from the classroom climate and the methodology to the delivery of the curriculum and the teacher-training strategies."
The problem, she realised, could only be fixed with support and input from teachers. Colbert's colleagues at the education ministry - where she had now started working - were shocked when she began arriving at the office with groups of teachers from impoverished rural communities in tow.
"Bringing them to work with me was very unusual," Colbert recalls, smiling. "But that made them visible [to policymakers]. We wanted to come up with an innovation that would impact national policy, something that was viable technically, so that any teacher could do it without a master's or PhD.
"It also had to be politically feasible [for the unions to accept]. Teachers had been given too much work. How could we help the teachers, rather than giving them more burdens?"
At the heart of the debate was the need to create a child-orientated pedagogy. While theories from the likes of Montessori and Piaget were already firmly established among academics, the challenge facing Colbert and Escuela Nueva's co-founders, Oscar Mogolln and Beryl Levinger, was how to make them practicable for poor rural communities.
After encountering resistance to change from within the ministry, Colbert set out to foster bottom-up support among teachers. A network of demonstration schools was established to put theories about child-centred learning to the test. "This allowed us to show people that it was working," Colbert says. "We wanted to initiate a demand-driven process. [We hoped] that the teachers would see how it worked and say, `This is helpful for us, we need it, we want it'."
And the pilots soon proved to be successful: retention and attainment levels rocketed. Crucially, the project engaged teachers, who had previously been burdened with a "very theoretical and academic" approach. "The teachers themselves were the actors of change," Colbert says. "It didn't take place at the ministry level."
The system also proved popular with parents. Students were free to learn at their own pace, which allowed them to help their families with the coffee harvest without having to drop out of school. And parents were encouraged to take part in their children's education, but in a way that suited them. "We made sure there were not so many meetings [for parents to attend] because that day, the poor don't eat," Colbert explains. "We needed flexibility to adapt to the children's conditions. They could finish academic units at their own pace. It's about children taking ownership of their learning."
Within two years, the naysayers at the ministry had been won over by Escuela Nueva's impressive results, and its radical new approach became official national policy. Unsurprisingly, Colbert's stock also rose, resulting in her appointment as the country's vice-minister for education. This in turn opened more doors. At the end of the 1980s, a loan from the World Bank allowed Escuela Nueva to expand into 20,000 schools across Colombia. The World Bank also rated the project as one of the three most important educational innovations globally, attracting widespread interest from overseas.
From methodology to movement
But political change closer to home began to give Colbert cause for concern. A move towards decentralisation, culminating in the Colombian Constitution of 1991, resulted in increased autonomy for the country's 32 departments (regions). Colbert feared that having to negotiate extra tiers of regional government would dilute the spirit of experimentation at the heart of Escuela Nueva. "I started seeing that innovations fade within bureaucracies. I can't say it very loudly," Colbert whispers. "But it's very difficult, and they are very vulnerable to political administrative changes."
In order to protect her creation, Colbert left her job and set up a non-governmental organisation, Fundacin Escuela Nueva, to promote and develop the model further. Since then, a host of spin-off programmes for secondaries, urban schools and migrant and displaced populations have also emerged. Colombian teachers have travelled the world to promote their teaching methods, resulting in forms of Escuela Nueva appearing in countries such as Brazil, Guatemala and Mexico.
Although Colbert and her team have given advice and guidance to interested parties, they have shied away from running overseas operations themselves and remain content for the teacher-led movement to be spread through partner organisations. "I don't want to grow my institution, I want to grow our impact," she says. "We're shifting from a methodology to a movement and we're spreading out."
And Escuela Nueva could even teach more economically advanced nations a lesson, Colbert believes: "It has had a real impact on peaceful, democratic behaviour through citizenship, entrepreneurship and leadership skills. This is what everybody's talking about right now. It's about 21st-century skills, what a computer cannot do.
"It's about learning to learn, learning to [show] initiative, learning to plan and meet deadlines, but especially learning how to work in teams. This is what businesses are looking for. We have a proven solution to improve quality in education, not only in the developing world but in the developed world."