For those who don’t know, the Programme for International Student Assessment (PISA) is a major cross-national study of 15 year olds’ academic abilities. It covers three domains (reading, maths and science), and since 2000 has been conducted tri-annually by the OECD. This study is widely respected, and highly cited, by some of the world’s leading figures – including our own Secretary of State for Education Michael Gove.
Unfortunately not everyone agrees that PISA is such an authoritative assessment. Over the last month it has come in for serious criticism from academics, including Svend Kreiner (PDF) and Hugh Morrison (PDF). These interesting and important studies have been followed by a number of media articles criticising PISA – including a detailed analysis in the Times Educational Supplement last week.
As someone who has written about (PDF) some of the difficulties with PISA I have read these studies (and subsequent media coverage) with interest. A number of valid points have been raised, and point to various ways in which PISA may be improved (the need for PISA to become a panel dataset – following children throughout school – raised by Harvey Goldstein is a particularly important point). Yet I have also been frustrated to see PISA being described as “useless”.
This is a gross exaggeration. No data or test is perfect, particularly when it is tackling a notoriously difficult task such as cross-country comparisons, and that includes PISA. But to suggest it cannot tell us anything important or useful is very far wide of the mark. For instance, if one were to believe that PISA did not tell us anything about children’s academic ability, then it should not correlate very highly with our own national test measures. But this is not the case. Figure 1 illustrates the strong (r = 0.83) correlation between children’s PISA maths test scores and performance in England’s old Key Stage 3 national exams. This illustrates that PISA scores are in-fact strongly associated with England’s own measures of pupils’ academic achievement.
Figure 1. The correlation between PISA maths and Key Stage 3 maths test scores
To take another example, does the recent criticism of PISA mean we actually don’t know how the educational achievement of school children in England compares to other countries? Almost certainly not. To demonstrate this, it is very useful to draw upon another major international study of secondary school pupils’ academic achievement, TIMSS. This has different strengths and weaknesses relative to PISA, though at least partially overcomes some of the recent criticisms, with the key point being – does it tell us the same broad story about England’s relative position?
The answer to this question is yes – and this is shown in Figure 2. PISA 2009 maths test scores are plotted along the horizontal axis and TIMSS 2011 maths test scores along the vertical axis. I have fitted a regression line to illustrate the extent to which the two surveys agree over the cross-national ranking of countries. Again, the correlation is very strong (r = 0.88). England is hidden somewhat under a cloud of points, but is highlighted using a red circle. Whichever study we use to look at England’s position relative to other countries, the central message is clear. We are clearly way behind a number of high performing East Asian nations (the likes of Japan, Korea and Hong Kong) but are quite some way ahead of a number of low and middle income countries (for example Turkey, Chile, Romania). Our exact position in the rankings may fluctuate a little (due to sampling variation, differences in precise skills tested and sample design) but the overall message is that we are doing okay, but there are other countries that are doing a lot better.
Figure 2. The correlation between PISA 2009 and TIMSS 2011 Maths test scores
Source: Appendix 3 of http://johnjerrim.files.wordpress.com/2013/07/main_body_jpe_resubmit_final.pdf
I think what needs to be realised is that drawing international comparisons is intrinsically difficult. PISA is not perfect, as I have pointed out in the past, but it does still contain useful and insightful information. Indeed, there are a number of other areas – ‘social’ (income) mobility being one – where cross-national comparisons are on a much less solid foundation. Perhaps we in the education community should be a little more grateful for the high quality data that we have rather than focusing on the negatives all the time, while of course looking for further ways it can be improved.
For details on my work using PISA, see http://johnjerrim.com/papers/