Why won't these teachers apply for pay rises?
With teachers in England staring down the barrel of a two-year pay freeze, most would grab any opportunity to increase the size of their salaries.
But in Mexico, where pay is already considerably lower than in the UK, seven out of 10 teachers are refusing the chance to be evaluated for pay increases of between 20 and a staggering 150 per cent.
Some 779,000 primary and secondary teachers avoided being evaluated on their academic and professional performance in 2010, according to education ministry the SEP.
More than 3,000 teachers won salary increases of between 20 and 150 per cent as a result of their evaluations. Yet most of these "successful" teachers scored only between one and four points out of a possible 20 in the section that tests how effective teachers are in imparting learning to their students.
An SEP analysis of national results for 2010 reveals that only 635,051 teachers demonstrated interest in being evaluated, out of a teacher population of more than 1,156,506.
Even so, only 377,460 actually submitted to the evaluation in order to be promoted or receive salary increases.
The evaluation procedure looked at each teacher's training history, the courses they had taken, classroom performance, the degree of learning experienced by students, the teacher's role in the school and the degree of participation in remedial programmes.
The education ministry's report shows that the scores of between one and four points were even obtained by teachers who held doctorate or masters degrees and had taken professional postgraduate courses.
Of those teachers who submitted to the tests, 1,841 had doctorates and 42,338 had masters degrees.
The report also revealed that among those evaluated there were 3,702 uncertified teachers - those who had only primary or secondary schooling or less, but who nevertheless managed to score sufficiently for them to receive salary increases.
The programme of teacher evaluation was one of the recommendations of the Organisation for Economic Co-operation and Development (OECD), following President Felipe Calderon's request for help.
In 2010, the education ministry allocated the National Education Workers Union (SNTE) the sum of around #163;18 million to finance the programme.
Mexico spends more per student than other countries that surpass it in educational achievement.
But critics point to the all-powerful teaching unions that decide which teachers get which jobs. Teachers graduating top of their class complain that they can't get jobs unless they belong to a union or unless they make payments.
Following a recent revelation that neither the government nor many state administrations know how many teachers are on their payrolls, partial checks unearthed thousands of "teachers" who neither taught nor worked in any administrative role.
This may go some way to explaining why so few wanted to draw attention to themselves by applying for pay rises.