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Thirty years on – a large anti-Flynn effect? The Piagetian test Volume & Heaviness norms 1975–2003


Correspondence should be addressed to Prof. Michael Shayer, 16 Fen End, Over, Cambridge CB4 5NE, UK (e-mail:


Background. Volume & Heaviness was one of three Piagetian tests used in the CSMS survey in 1975/76. However unlike psychometric tests showing the Flynn effect – that is with students showing steady improvements year by year requiring tests to be restandardized – it appeared that the performance of Y7 students has recently been getting steadily worse.

Aims. A sample of schools sufficiently large and representative was chosen so that the hypothesis of worsening performance could be tested, and estimated quantitatively.

Sample. Sixty-nine Y7 school year groups containing pupil data on the Volume & Heaviness test and the University of Durham CEM Centre MidYIS test were located giving a sample of 10, 023 students covering the years 2000 to 2003.

Method. Regression of the students' school mean on Volume & Heaviness on the schools' mean MidYIS 1999 standardized score, and computing the regression at MidYS = 100 allows comparison with that found in 1976.

Results. The mean drops in scores from 1976 to 2003 were boys = 1.13 and girls = 0.6 levels. A differential of 0.50 standard deviations in favour of boys in 1976 had completely disappeared by the year 2002. Between 1976 and 2003 the effect-size of the drop in the boys' performance was 1.04 standard deviations, and for girls was 0.55 standard deviations.

Conclusion. The idea that children leaving primary school are getting more and more intelligent and competent – whether it is viewed in terms of the Flynn effect, or in terms of government statistics on performance in Key Stage 2 SATS in mathematics and science – is put into question by these findings.