Yesterday Full Fact asked whether, through using the less comprehensive Office for National Statistics (ONS) figures, The Guardian had overstated the rise in net UK migration over the last year.

The paper's report on the latest ONS immigration statistical release, stated that net migration had 'jumped' by 100,000 in the last year.

As we explained last time, this is based on the figures from the International Passenger Survey (IPS) migration data instead of the Long-term International Migration (LTIM) figures; which are more complete and comprehensive, for example taking into account asylum seekers. The table below shows the figures from both measures.

However, despite the ONS warning on the provisional nature of the IPS data, and Oxford's Migration Observatory telling us that the IPS data is often significantly different from the LTIM equivalent figures, several more papers today focused on the headline grabbing IPS figures.

The Times ran on very similar lines to the Guardian, reporting that: “Shock rise in immigration by 100,000 dents targets. Despite the Government’s ambition to cut immigration, figures released yesterday show a surprise jump of almost 100,000 in the past year.”

This headline not only focused on the less complete IPS figures, but is also wrong to then headline a rise of 100,000 in immigration. According to the IPS figures, there was a rise in net migration close to 100,000 which is attributable to rising immigration but also falling emigration.

Similarly, The Express were pulling no punches with their reporting, announcing: “The startling figures coincide with net migration in the year to September 2010 being the highest for five years at 242,000, up 96,000 on the previous year.”

At first sights, the Daily Mail was one of the few papers to focus instead on the more complete LTIM figures, publishing the ONS headline graph of changing migration over the last few years.

However, the paper then inexplicably resorts to mixing the LTIM and IPS net migration figures to state that: “The net migration of 242,000 [LTIM was nearly 100,000 higher than the previous year. [Compared to IPS]" 

The article continues: "The net migration figure of 242,000 [LTIM] was 96,000 up in a year [Compared to IPS] and nearly 50 per cent higher than the 163,000 annual figure [LTIM] estimated in the year to December 2008."

This mixing of the LTIM figure for net migration for the year to September 2010 with the IPS net migration figure for the year to September 2009 is simply bad statistical practice.

The Sun was more accurate in reporting the percentage change in net migration, stating that: “Migration rockets 45% in just a year. A SHOCK rise in immigration has left David Cameron's vow to slash numbers in trouble. Net migration rocketed to a six-year high of 242,000 in 2010 - an astonishing 45 per cent rise in just 12 months. But the Office for National Statistics revealed yesterday the figure has shot up from 166,000 in June 2009 to 242,000 last year.”

This is backed up by the figures. While a better comparison with the year to September 2010 might be the year to September 2009, no statistics are available to do this.

Amongst all of the attention grabbing headlines on immigration, it was left to The Mirror to report on a more modest rise in net immigration. Noting the Prime Ministers aspiration to reduce immigration to the tens of thousands, they reported: “But Government statistics show net immigration up seven per cent. Last year 586,000 moved to the UK, while 344,000 left.

This seven per cent figure is reached by comparing the change in LTIM net immigration figures for the year to June 2010 with those for the year to September 2010. Arguably, in making the link between increasing net migration and the Government's current policy stance to migration, The Mirror is using the best figures available, although comparing figures a few months apart rather than year-on-year figures could potentially be distorted by seasonal changes.

Conclusion

Press reporting on the latest migration figures from the ONS has clearly highlighted the dangers in not explaining what the figures are showing and representing, as well as in mixing and matching across data sets in search of a good headline.

While the Sun and the Mirror were on this occasion reporting correctly on the migration figures, the Times and the Daily Mail were statistically incorrect in the comparisons that they drew, while the Express failed to explain the limitations of the IPS figures when using them.