The purpose of this study is to identify school factors that affect students' achievements at the secondary and tertiary levels of education. The analysis included data of 9,894 students who studied in Auckland regional secondary schools in 2004. The results indicate that, although student demographic characteristics are associated with students' pathways and achievements, schools' demographic composition did not affect student outcomes. It was found, however, that schools' organisational factors do have an effect. At the university level, none of the schools' characteristics was related to students' achievements at the higher end of the achievement scale (GPA greater than or equal to 4). However, students from private or state-integrated schools were found to be more likely to achieve low GPA (less than 2) than students who came from state schools. In conclusion, it is suggested that interventions targeting at-risk populations based on demographic factors should focus on individuals or groups rather than on institutions; while school-based interventions should identify the schools by their structure and function rather than by their demographic characteristics.