Schools with a high turnover of pupils should be given extra funding, as young people who change schools frequently have troubled lives, a major research conference was told this week.
Pupils who move schools in the two years before they sit their GCSEs are only half as likely to gain five good grades, according to Feyisa Demie, head of research in Lambeth, south London .
Mr Demie said it was not the upheaval of the move itself that affected performance but the reasons behind it - such as family breakdown, the imprisonment of a parent or exclusion from an earlier school. Affluent pupils with stable families were affected much less when they moved schools.
The troubled personal lives of many school-changers left them facing an uphill struggle to gain their GCSEs, he said.
Only 22 per cent of pupils in Lambeth who moved school during key stage 4 achieved five Cs or better, compared to 44 per cent of those who stayed at the same secondary, the Government-funded study found.
Mr Demie was presenting the findings of his study on pupil mobility to the British Educational Research Association conference in Manchester.
More than 1,300 academics from across the UK and overseas are at the University of Manchester Institute of Science and Technology to share their work with delegates from countries as far afield as Ethiopia and Japan.
Titles range from the esoteric A Case Study of the Best Practice in Gifted Education in Palestine, to the incomprehensible Conceptualising Professional Learning for Multi-Agency Working and User Engagement.
Hot topics at the three-day event which ends on Saturday include how to make maths more attractive to pupils, the status of teaching and pupil behaviour.
The study was carried out by Mr Demie and Dr Steve Strand, of education publishers NFER-Nelson, who is also a member of BERA's executive committee.
Although the research suggests secondary pupils who switch schools have problems adjusting to new routines, rules and curriculum, Mr Demie blamed underlying problems for poor performance. Pupils moving because of family breakdown, domestic difficulties, imprisonment of a parent or who arrived in the UK as refugees were more likely to experience problems than children of professionals who moved for career reasons.
Mr Demie said: "The overwhelming message from this and other research is that schools with high levels of pupil mobility need to be resourced to meet this challenge." Nine in 10 Lambeth heads supported the idea, he added.
The difference in attainment between pupils who move school and the rest could partly be explained by the fact that a disproportionately high number came from overseas, had a disadvantaged background or special needs, the study found.
Once these background factors were taken into account, pupils who moved school and those who did not made the same progress between ages seven and 11.
About one in five pupils in the south London borough are classed as mobile -although the rate varies sharply between schools.
Final results of the research on pupil mobility will be presented at a government-backed conference in December.
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