Measures of variability are successfully used in predictive modeling in research areas outside of education. This study examined how standard deviations can be used to address research questions not easily addressed using traditional measures such as group means based on index variables. Student survey data were obtained from the Organisation for…

Transition to middle school in Portugal is associated with increased levels of stress for students, as well as an increase in grade retention. This study investigated the impact of a school adjustment program designed to support students during this transition, and its differential results by gender and fourth-grade class size. Multilevel linear…

This paper explores parental involvement using principal and parent survey reports to examine whether parents' involvement in their children's schools predicts academic achievement. Survey data from principals and parents of seven countries from the PISA 2012 database and hierarchical linear modelling were used to analyse between- and within-…