John C. Nesbit and Olusola O. Adesope (2006) extracted fifty five (55) studies from sixty seven (67) standardized mean difference effect sizes and got five thousand eight hundred and eighteen (5,818) participants. It proved that concept mapping studies split by educational level (the mean effect size of grades 4 to 8 is 0.905,the highest among all levels), class setting(the mean effect size of not entirely in class is 1.039 ), subject(the mean effect size of humanities, law and social studies is 1.265,the highest among all subjects), duration(less than 5 weeks reporting the mean effect size of 0.701,the highest among all duration) and the way of learning(the mean effect size of maps constructed is higher mean effect size with 0.819 than that of maps studied).