Monrovia - On a weekday morning in Cecelia Dunbar school, a bumpy hour's drive from Liberia's capital, a group of seven-year-olds concentrate on their maths lesson, seated at individual wooden desks.Children at schools like Cecelia Dunbar read and count at a level improved by 60% from a year ago - proof, according to the government and private education companies, that a bold experiment for one of the world's worst education systems has succeeded."The approaches that each of the providers are bringing in are showing results," said Christina PioCosta-Lahue, the managing director of Rising Academies Liberia, which operates 29 schools on the government's behalf under the Partnership Schools Programme launched last year."A student in first grade (six to seven years old) has made two years of progress in reading," PioCosta-Lahue said.Liberia's infrastructure and its education system were ravaged by 1989-2003 back-to-back civil wars and a subsequent deadly Ebola outbreak which closed schools for months.Last year, the UN children's agency ranked the small west African nation worst globally in terms of access to primary education, on a continent whose education systems are already the worst-performing worldwide.A lack of text books, school sanitation, public transport and parents keeping children out of school to earn or help them work are common.The government and private firms therefore celebrated a random control trial conducted by US development thinktank the Centre for Global Development (CGDEV) which found that beyond the improved literacy and numeracy, pupil enthusiasm has also measurably lifted.However, critics remain sceptical that such initiatives can overhaul national education standards, whether in Liberia or in Kenya, Nigeria and Uganda where similar schools operate.Sustainable? More African children are in school than ever before and more than a fifth of the continent's children are currently privately educated, a number that is likely to rise, according to a report released by education-focused consultancy Caerus Capital in April.The main change at Cecelia Dunbar has been in teacher training, monitoring and accountability, saids principal Jacob Haiwulu. "They carry out evaluations for our students and provide training for teachers," Haiwulu said, referring to the partner company. "You always have a target to achieve."The CGDEV study found that while students in partnership schools enjoyed better quality education with more teachers per pupil, the schools had higher costs and some pupils were reassigned to government schools to keep class sizes capped."The program has yet to demonstrate it can work in average Liberian schools, with sustainable budgets and staffing levels, and without negative side-effects on other schools," it noted.Liberia's main teachers' union, whose leadership has opposed the programme from the start, says the money flooding into these schools was bound to bring results, pointing to their fruitless campaigns for more resources.Deeper roots But teachers in government schools say the main problem with Liberia's schools has more familiar roots: poverty and corruption.William VS Tubman High School in central Monrovia is one of the country's best, equipped with a few computers, a canteen and bathrooms: facilities lacking in the vast majority of state and privately-run schools.But even here teachers struggle to get to class on time as they moonlight to supplement meagre salaries."You can't support your family with $240 (a month) in Liberia," history teacher Boniface Colley told AFP."It is also the management of the little resources that we have, we have problems with managing and allocating it correctly," he said, alluding to waste and endemic graft in the government.President Ellen Johnson Sirleaf's administration has made efforts to lift "ghost" workers, including teachers, off the state payroll."We have a lot of resource constraints ... so we look for international organisations to help us service the needs of our citizens," Gbovadeh Gbilia, Deputy Minister for Planning, Research, and Development, told AFP.A support worker who regularly visited William VS Tubman said poverty affected students' ability to learn and to stay in school.Girls began dropping out once they began menstruating, embarrassed to come to class without sanitary pads, while others quit school after pregnancies became too obvious. More than 30% of Liberian girls have a child before the age of 18.Boys were often too hungry to concentrate as they couldn't afford to eat in the canteen after coming to school without breakfast, the worker said on condition of anonymity.Alassis Goldore, the principal of William VS Tubman, said the civil wars have scars that were sometimes hidden."It requires much more resources to replenish or replace these things that were destroyed," he said.