Jordan, V & Brownlee, L., (1981) Meta-analysis of the relationship between Piagetian and school achievement tests. Presented to American Educational Research Association, Los Angeles, CA.
I have not been able to get a full copy of the paper but was able to get a copy of the summary:
'The relationship between Piagetian and school achievement tests was examined through a meta-analysis of correlational data between tests in these domains. Highlighted is the extent to which performance on Piagetian tasks was related to achievement in these areas. The average age for the subjects used in the analysis was 88 months, the average IQ was 107. Mathematics and reading tests were administered. Averaged correlations indicated that Piagetian tests account for approximately 29% of variance in mathematics achievement and 16% of variance in reading achievement. Piagetian tests were more highly correlated with achievement than with intelligence tests. One implication might be the use of Piagetian tests as a diagnostic aid for children experiencing difficulties in mathematics or reading.'So once again a proper experiment is not used but rather a correlational analysis which is then converted by Hattie into an effect size.
Professor Pierre-Jérôme Bergeron (2017) highlights the issue:
'Hattie confounds correlation and causality when seeking to reduce everything to an effect size.' (See Effect Size for details).NOTE: Correlation studies do not satisfy The U.S. Department of Education's design or quality criterion.
'in addition to mixing multiple and incompatible dimensions, Hattie confounds two distinct populations:
1) factors that influence academic success and
2) studies conducted on these factors.'
'... one [Hattie] has not investigated how a concrete measure tested in school affects the students' skills, but the connection between different relationships.'
They then continue to discuss this influence in detail,
'... a strange result when programs based on Piaget's theory are placed high on the list with the second best effect. According to the report, however, this is based on an investigation that has looked at the relationship between Piaget's skills and reading and mathematics ... Not surprisingly, one finds a high degree of correlation, since all the factors here are cognitive relationships related to learning. Based on this, the conclusion has been drawn that programs based on Piaget's theory have a very good effect. Such a conclusion must be said at best, to be based on very thin grounds.'Mike Bell, who runs the Evidence-Based Teacher Network (very pro-Hattie) says :
'the research Hattie cites only refers to the fact that if you assess students using a Piagetian test of thinking level (not on the topic), and then give them a subject/topic test, there is a close correlation. It does not refer to the effectiveness of a Piagetian program.'From docendo
"I have made a few enquiries and will update this post if I get hold of the full text but it seems quite close to my assumption that it’s about a correlation between tests of Piagetian stages and achievement. I don’t think that’s of any direct use since it doesn’t tell us anything about how we accelerate progression through the stages."Once again there are significant doubts about the validity of this meta-analysis and therefore the high effect size. It does not appear to measure what Hattie implies it measures.
VERDICT: the quality of evidence Hattie presents for this influence is very poor. I do not believe it is valid to make the claims that Hattie does. So will this advance a child's achievement by 3 years? I very much DOUBT it!
Lervåg & Melby-Lervåg (2014) then advise,
'Instead of looking at Hattie's summary, it is a far better idea to go to some of the meta-analyzes or good randomized controlled studies that have been published recently.'