# BETWEEN-SCHOOL DIFFERENCES IN THE STRENGTH OF THE ASSOCIATION BETWEEN INTELLIGENCE AND SCHOOL ACHIEVEMENT IN MATHEMATICS

Does intelligence predict school achievement in mathematics? The answer is obvious (e.g Deary, Strand, Smith & Fernandes, 2007; Hofer, Kuhnle, Kilian & Fries, 2012). Much less obvious is whether the strength of this relationship differs between schools or classes. We used data collected over two waves of school effectiveness study conducted by Educational Research Institute (Warsaw, Poland) to answer this question. We analyzed data of over 4700 students from 172 schools and 300 classes gathered when children were in third grade of primary school (fluid intelligence and controlled variables: sex, age, SES, parentsâ€™ education level) and one year later (mathematics scores). The results show that (1) there are significant between-school differences in the strength of the relationship intelligence-mathematics achievement and (2) this strength negatively correlates with average achievement in mathematics on the school level. Possible explanations are discussed.