If London were a country, how would it do in PISA?

8 October 2019

By John Jerrim

Since 2009, parts of China have been participated in the OECD’s triennial PISA testing.

In 2009 and 2012, Shanghai topped the international rankings and by quite some distance, with 15-year-olds in this Chinese city estimated to be up to two and a half years ahead of their counterparts in England.

Yet China’s participation in PISA also led to controversy.

Why was it allowed to enter just Shanghai into the study, rather than a random sample from the whole country, as other nations are required to do?

In England, London tends to outperform other parts of the country in terms of GCSE performance. Might London then rival Shanghai if it too were included as a separate entity in the PISA rankings?

Let’s look at the evidence.

London did not perform so well in PISA 2009 and 2012

In one of my papers published since the last PISA results [PDF] I tried to estimate how pupils in London performed in PISA. The results from this exercise can be found in the table below.

Actually, London did not fare too well in the results. With an average maths score of 479, reading score of 483 and science score of 497, it was below both the OECD average and the scores for the rest of the UK. In maths, pupils were three years behind 15-year-olds in Shanghai. 

One obvious question to ask, then, is why is there no evidence of a “London effect” in PISA?

It’s hard to say for sure. But, by using the fact that PISA results have been linked to the National Pupil Database, I was able to find some clues (keeping in mind that GCSEs and PISA tests are taken just six months apart).

Most importantly, the analysis showed how pupils from disadvantaged and ethnic minority backgrounds in England were likely to do much worse on the PISA test than one would anticipate, given how they performed in their GCSEs. For instance, black and Asian teenagers scored almost 30 PISA points lower than predicted (given their GCSEs).

Of course, as an ethnically and socially diverse city, London has a disproportionately large share of ethnic minority and disadvantaged pupils. Once this has been controlled for, the difference between London and the rest of the UK was vastly reduced. 

Regional variation in PISA 2015

Regional variation in PISA scores in England was also something I considered in work on PISA 2015 [PDF]. The key results are in the table below.

Interestingly, London seemed roughly in line with the England average in the PISA 2015 results. Yet it was still some way behind the top-performing area (the south east), with a difference in science of around 30 PISA test points (in statistical terms, an effect size of 0.3). At the other end of the table was the north west and north east, and the west Midlands, which brought down England’s average PISA score.

Key message

So although London schools may outperform the rest of England in GCSE examinations, there is no evidence that the same is true in PISA.

More work needs to be done to understand why pupils from ethnic minority and disadvantaged backgrounds perform so differently across these two assessments. 

Other posts in this series can be found here, here and here.