Number of ex-students living in the UK unclear after official stats deemed unreliable
Statisticians told to refer to estimates on emigration of former students as ‘experimental’
THE NUMBER of ex-students living in the UK could be vastly different than previously thought after the official statistics were deemed unreliable.
The official measure is to be downgraded after a watchdog raised concerns it does not bear the weight of public scrutiny.
And statisticians have now been told to refer to estimates on emigration of former students as "experimental" - after a review concluded they do not provide a complete and coherent picture.
The numbers of foreign students have repeatedly been at the centre of controversy, with Theresa May under pressure to remove them from the overall net migration target of 100,000.
But scrutiny has also focused on a gap between the estimated number of migrants who enter the UK to study and the number of former students recorded as then leaving the country afterwards.
The discrepancy has fuelled questions over whether students are remaining in the country beyond the end of their courses - or whether the large-scale survey used to compile migration estimates is failing to capture departures.
After concerns were raised about the "robustness" of the former-student emigration figures, the Office for Statistics Regulation carried out a review.
Publishing the findings on Thursday, Ed Humpherson, director general for regulation at the OSR, flagged up concerns the former-student emigration estimate "does not bear the weight that is put on it in public debate".
He said: "This estimate should add clarity on the pattern of student migration in the UK, but instead, it creates doubts by not providing a complete and coherent picture of former student emigration, since these figures alone do not provide information on all the different outcomes for international students."
Between 2012 and 2015, the estimate of student immigration has been considerably higher than the estimate of former-student emigration, fluctuating from one year to the next but averaging around 110,000 a year, according to the report.
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Although there are caveats to comparing the two figures, the OSR said the size of the "student migration gap" has remained relatively stable.
This raises questions as to whether students are remaining in the UK in the number suggested by the International Passenger Survey (IPS), upon which the estimates are based, or whether the IPS does not capture their departure, or a combination of the two, the paper said.
Mr Humpherson emphasised the findings apply only to the student component of the migration figures, and are not a judgment about the quality of overall estimates of immigration and emigration.
The ONS said it is happy to comply with the requirement to label statistics produced on migration of former students as experimental.
It added: "This is a complex area and it forms a key part of our work programme to develop more reliable migration data in areas which the International Passenger Survey was not originally designed for.
"We are pleased that the Office for Statistics Regulation has noted that this judgement does not reflect on the overall quality of the figures on international migration."