Readings: - Clinical and Psychosocial Factors Associated With Ach...

The study of Harell et al. (1996) entitled “Effects of a school-based intervention to reduce cardiovascular disease risk factors in elementary-school children: the Cardiovascular Health in Children (CHIC) study” was a randomized controlled field trial aimed to answer the important scientific question does a school-based intervention could reduce cardiovascular disease risk factors in third- and fourth-grade school children. The authors used an experimental study design since they actively introduced an intervention to one group of children in the form of an 8-week exercise program and classes on nutrition and smoking. Comparisons were made between different persons, children from the control group, and intervention group. The control over confounding variables was achieved by randomization at the school level, homogeneity at the individual level by including children with similar characteristics, and at the end the statistical control of confounding variables by using statistical control