Although the essential role of school leaders in school improvement processes has been confirmed in the literature, the link between school leadership and student outcomes has only been recently addressed. Research suggests that the effect of school leaders on student outcomes is mediated through the creation of certain school conditions. Our study aimed to verify the mediating effect of some school conditions on the school leadership and student outcomes link. Based on empirical data collected from the principals and key staff in 49 secondary schools in Hong Kong, our results showed that staff collaboration was a mediating factor influencing the link and it was more commonly found in schools whose leaders were more attentive to the professional development of teachers.

The increasing demand on school principals to raise student achievement in the accountability era has brought the attention of researchers back from transformational leadership to instructional leadership. Traditionally, these two leadership types have been considered separately in the literature. While researchers often advocate one type in favour of the other, this study argues that both types are important to schools and attempts to simultaneously examine their influence on school effectiveness. Based on the empirical data collected from 48 Hong Kong secondary schools, the results have shown that the schools with stronger orientation towards both instructional leadership and transformational leadership outperformed the schools with weaker inclination on both leadership styles. Discussion in the Hong Kong context is provided.