2.2. Randomization
allergies
ALLERGIES
A randomization procedure of the classrooms (a computer-generated list of random numbers using SPSS, version 24) was carried out by the two lead researchers (A.M. and S.M., co-authors). After all of the children and parents completed the baseline assessment, the classrooms were randomized. The baseline assessment consisted mainly of the participants’ anamnesis, i.e., information about surgeries, immunizations, allergies, and illnesses and results of physical exams and tests. Furthermore, information was collected on sports activities, including those of a competitive nature, which were carried out by the participants outside school hours. This evaluation was made through a questionnaire addressed to the parents followed by, only if necessary, a subsequent interview. The basic information required for randomization (initials and participant code, age, weight, and height) was stored in a database. The randomization was stratified by school and grade ensuring that in each school there were both control and intervention classes and that the number of control and intervention classes was balanced between the two grades.