This study has tackled the thorny problem of closing the Student Achievement Gap (SAG) in California's elementary schools. To address that problem, an "Integrated" form of educational leadership called Transformational Instructional Leadership (TIL), a form grounded in "best practices" of Transformational and Instructional leadership, was developed. TIL was then tested using a quantitative, one-shot, two-group, survey-based, quasi-experimental, evaluation research design in four elementary schools from a local district undergoing program-based school improvement/reform to address its "gap" issues in English and Language Arts (ELA). Descriptive and non-parametric inferential statistics were used to determine if in implementing the same program--Response to Intervention (RtI), schools whose leaders evidenced greater TIL, based on the perceptions of their Lead Teachers, reduced their SAGs more than schools whose leaders evidenced less TIL. TIL added some "value" to the RtI program-based school improvement/reform effort to "close" these schools' ELA SAGs, but not as much "value" as the RtI effort itself. The study's findings did not support the general viability of the TIL concept. They did support TIL's specific viability for ensuring the faithful implementation of the program-based school improvement/reform. In sum, the findings suggested that "Integrated" forms of educational leadership, like TIL, if they are to address the Student Achievement Gap problem, should move more along program-based, instructionally-defined lines than they have in the past. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]