TY  - JOUR
T1  - PHysical activity is not related to performance at school—reply
AU  - Singh AS, Uijtdewilligen L, Twisk JR, van Mechelen W, Chinapaw MM
Y1  - 2012/07/01
N1  - 10.1001/archpediatrics.2012.337
JO  - Archives of Pediatrics & Adolescent Medicine
SP  - 678
EP  - 679
VL  - 166
IS  - 7
N2  - 
In their letter, Hattie and Clinton report that they have performed a meta-analysis averaging all outcomes from all included studies.1 We, however, believe that the heterogeneity of the included studies is too large to combine them in a meta-analysis. The included studies differ largely regarding study sample, intervention contents, measurement instruments, outcome variables, follow-up duration, and study design. Therefore, we believe that the data are not appropriate to perform a meta-analysis. Instead, we chose to perform a methodological quality assessment combined with a best-evidence synthesis2 to summarize the findings of all studies. This method is commonly used in systematic literature reviews and takes into account the number, methodological quality, and consistency of outcomes of the studies. Based on this method, we conclude that there is strong evidence for a positive prospective relationship between physical activity and school performance.1 Importantly, this conclusion is very different from the statement that we found “evidence for a strong positive relationship.”

SN  - 1072-4710
M3  - doi: 10.1001/archpediatrics.2012.337
UR  - http://dx.doi.org/10.1001/archpediatrics.2012.337
ER  -