Context
Sample
The study presented in this article is a quasi-experimental study and was conducted during the school year 2008–2009, in 13 primary schools in Cyprus. Convenience sampling was used to select elementary classrooms (n = 24 classrooms, n = 479 students) to participate in the study. All 4th grade elementary teachers from Nicosia District were invited to participate in the study. Nevertheless, only 28 teachers responded to the call and finally only 24 participated (Nmale = 1, Nfemale = 23). All participants were experienced teachers (with 10 to 17 years of teaching experience). None of the participants had any further academic qualifications. Their knowledge on differentiated instruction was limited and was gained through one-shot lectures and conference presentations. They all shared the opinion that differentiated instruction is needed, but not all of them believed that it was possible or viable in the mixed ability classrooms. Students included in this study were those who were allocated to the participating teachers. Their age ranged from 101 to 112 months (around 8.7–9.7 years old). A total of 479 students participated in the study. The total sample consisted of 246 (51.4%) girls and 233 (48.6%) boys. The
sample was divided into an experimental (nexpclass = 14) and a control group (nconclass = 10) based on the teachers’ choice on whether to attend or not the professional development program which was specifically developed for the purposes of the current study. All classrooms were of mixed ability since this constitutes a basic characteristic of the Cypriot educational system. According to the teachers’ records, there were pupils from five different academic levels in all classrooms.