"The mental age of an average adult Gypsy is thought to be about that of a child of 10," said the 1959 edition of the Encyclopaedia Britannica, 14 years after the end of the Nazi genocide of Romany Gypsies. This week new analysis of the 2011 census has been released by the Office for National Statistics. It revealed that of the 58,000 people who identified themselves as being of Gypsy/Traveller ethnicity, 60% had no formal qualifications whatsoever. This is almost three times higher than the figure for England and Wales as a whole, which is 23%.

It's a depressing picture that will be all too familiar to those still specialising in Traveller education, following severe government cuts to provisions. Progress seems horribly slow since the 1967 Plowden report, when things were nonetheless far worse: fewer than 10% of Gypsy and Traveller children went to school at all, and almost all adults were completely illiterate.

In a modern context, the figures still paint a bleak scene. Yet this cannot simply be put down – as the Britannica once claimed – to a basic lack of potential among Gypsies to excel in education. The reality behind these figures is a complex web, a series of factors influencing how Gypsies and Travellers do at school and in further and higher education.

Even teachers with long years of experience working in these communities find it hard to agree on which variables are the most important. As one secondary school headteacher, quoted in the Department for Education's 2010 report Improving the Outcomes for Gypsy, Roma and Traveller pupils, said: "Why are [Gypsy, Roma and Traveller] pupils underachievers? Probably, persecution and racism. They are very self-sufficient, and not trustful of routes society provides for progression." Yet other teachers mention children's parents "colluding, sabotaging aspirations", and refer to "scripts", commonly heard rationalisations based on bullying and the irrelevance of school, which get trotted out, regularly and frustratingly, by Gypsy and Traveller parents.

These are all the opinions of experienced teachers and shouldn't be taken lightly, but neither should less polarised views like those of this teacher: "It varies from family to family really … I have a chap in my class, his mum reads with him every night and does all the work that is sent home …[others] don't have the resources at home and obviously literacy skills to do so."

This chimes with my own experience. While I went home to three generations of Romany Gypsy women who believed in literacy and read with me as often as they could, other families had different priorities, with some still believing that "rithmetic" is the only "R" that a Gypsy really needs in order to earn a living.

Many adult Gypsies and Travellers are recognising the importance of education, as the painstaking yet upward post-1960s trend shows. Some return to learning in adulthood, from basic literacy and numeracy schemes such as Toe-by-Toe to media skills training for Travellers provided by the Rural Media Company, and much else besides.

But there are other things to bear in mind about the data from the census. Organisations including the Traveller Movement have argued cogently that 58,000 Gypsies and Travellers – which is far fewer than the 200-300,000 estimated to live in Britain by the (then) Commission for Racial Equality in 2004 – probably represents a significant undercount. The report also tells us little about Roma migrants from eastern Europe, where segregated schooling is rife: these people were estimated to number 200,000 in a recent study conducted by Salford University. Lastly, the ONS makes no mention of the total absence of material on Romany and Irish Traveller history in the national curriculum, including the Romany and Cant languages. In this context, it's unsurprising that many Gypsies and Travellers still question whether, as the 21st century wanders on, an outsider's education can ever really be for them.