FOR most of her life, Ana Silva was illiterate, even though she completed primary school. Then she joined Misión Robinson, a literacy programme organised by Venezuela's president, Hugo Chávez. Once a hospital cleaner, she is now a nursing auxiliary and hopes to study social work in Cuba. Her colleagues at work no longer have to help her decipher her payslip. “We live better,” she says. “We live like people.”

Mr Chávez's supporters would like the world to believe that Ms Silva's story is typical of the way their hero has revolutionised the lives of his country's poor. Sadly, there is growing evidence that in fact it is exceptional.

The literacy scheme was one of a clutch of social “missions” organised by Mr Chávez in 2003, when he faced possible defeat in a recall referendum on his presidency. The government claims that by October 2005 it had all but eliminated illiteracy. That claim has become a centrepiece of the international propaganda effort on behalf of Mr Chávez's “revolution”. But there is no data to support it. Many educationalists doubt it. Even the government itself has retreated from its initial figure of “less than 1% illiteracy” to a figure of around 4%, though it is not clear whether this refers just to adults or to the total population.

It is notoriously difficult to obtain precise literacy figures from census data, which rely on self-assessment. But Francisco Rodríguez of Wesleyan University in Connecticut and Daniel Ortega of IESA, a Caracas business school, have used household surveys from the national statistical institute to assess the programme. In an article in the latest issue of Foreign Affairs, Mr Rodríguez says that they found “little evidence” of any “statistically distinguishable effect on Venezuelan illiteracy”. Where the government says it taught 1.5m, the study found that only 1.1m were illiterate to begin with, and that the fall over the 2003-05 period was less than 100,000. Even this improvement could largely be explained by a long-term demographic trend (many illiterate adults are elderly and die off).

Adán Chávez, who is the education minister as well as the president's brother, has complained of statistical “manipulation” by the government's foes. But Mr Rodríguez, for one, is no reactionary; he was the chief economist of Venezuela's National Assembly in 2000-04, and was once a chavista sympathiser.

Last year the statistics institute launched its own study on the impact of the social missions. This was supposed to be ready by January. But delays in buying equipment mean it has yet to start, according to Irene Gurrea, the economist in charge. Asked if there were any reliable statistics on the impact of Misión Robinson, Ms Gurrea said: “As far as we know, no—that's why we're doing the study.”

Staff of an older literacy programme run by Fe y Alegría, a Catholic charity, say they continue to enroll students. In Machiques, near the Colombian border, 100 joined in the past semester. They say that up to 40% of the Warao Indians in the Orinoco delta are illiterate. In 2005 Mr Chávez told local officials to declare their towns officially “illiteracy free”. Knowing this to be untrue, the mayor of Machiques resisted, but gave in to pressure, according to Jesús Vilorio, who works for Fe y Alegría.

It is not hard to find individuals like Ms Silva who say their lives were changed by Misión Robinson. But the missions have gone hand-in-hand with neglect of schools and hospitals. Mr Rodríguez estimates that Robinson spent $1,000 for each of its literate graduates, compared with around $60 for other literacy schemes in Latin America. At the least, that money could have been better spent.