DEVELOPMENT, FACTOR STRUCTURE AND RELIABILITY OF THE SHARED INSTRUCTIONAL LEADERSHIP SCALE (SILS)

This study investigates the construct validity of a survey measuring shared instructional leadership (SIL) in secondary schools. SIL emphasizes collaborative undertaking of leadership responsibilities among school staffs. The importance of shared contributions from school staff in instructional leadership has received rich attentions from educators and researchers. The involvement of school staffs in school leadership responsibilities facilitates wise decision making processes about instructional matters. Also, it increases teachers’ efficacy, which leads to higher effectiveness of teaching, promotes high-quality instructions, and facilitates student achievement (Lambert, 2002; Marks & Printy, 2003; Lee, Hallinger, & Walker, 2012; Goddard, Hoy, & Hoy, 2000; Weiss & Pasley, 2004; Goddard, Goddard, Kim, & Miller, 2015).

Although there exists a rich collection of empirical working about the forms of SIL, there is a lack of measurements specifically assessing SIL. A measurement specifically assessing SIL can facilitate research related to this issue. The scale of instructional leadership developed by Hallinger and Murphy (1985) provides founding measurement of instructional leadership. Related measurements and indicative raters developed later by researchers and educators involve new aspects such as collaborative input from school staffs, providing insights in developing the items of SIL.

This study develops a survey measuring SIL with a focus on the collaboration between school staffs. The survey highlights the main contents of instructional leadership practices, including communication and development of instructional vision, securing resources for high-quality instruction, decision-making processes, data examination, community-partnership development, and continuous instructional improvement. It uses a 6-point Likert scale (1-strongly agree, 2-agree, 3-somewhat agree, 4-somewhat disagree, 5-disagree, 6-strongly disagree). Four exploratory factor analyses were conducted respectively based on four sub-samples generated from a sample of teachers recruited from public secondary schools in a Midwestern state of the U.S. (N=420). The sub-samples included one individual-level sample and three school-level samples. The factor structure remained stable across the four sub-samples. A confirmatory factor analysis was conducted in one of the school-level samples (N=103). Its results confirmed the unidimensional structure (α= .92). This study also discusses the implications of the measurement’s quality and applicability, as well as the direction for further validation.