Implementation of the Australian Curriculum has seen conflicting policy documentation create inequality in music education, particularly at the transition to secondary school. The level of music knowledge assumed by the curriculum documentation is not being met on entry to high school, as primary (elementary) schools are only required to provide one strand of The Arts (Education and Training Committee, 2013), leaving some students with no primary music education. With financial constraints regularly identified as a reason for omitting music programs, music education is increasingly becoming the domain of wealthy, independent/private schools, limiting opportunities for success for students from lower socio-economic backgrounds. Moreover, literature indicates that in a climate of diminishing curriculum time and multifarious cohorts, teachers are tending to “teach to potential”, intensifying the disadvantage for students with limited prior learning. With research into formative assessment data use and Direct Instruction (DI) showing improved outcomes for students, the researcher hypothesised that regular formative assessment, item analysis and direct instruction may address inequity, close the gap and improve learning outcomes for students with varied prior learning and skill levels during the first year of high school. This mixed method study tracked students’ music literacy skills in the first year of high school through formative assessment data and written student reflections. Pilot tests were developed and trialled over a three-year period and then implemented at the research site; a multi-campus, school situated in metropolitan Melbourne. Over eighteen weeks, students completed the series of three multiple choice tests based on music literacy skills as set out by the Australian Curriculum. Data were collected from two classes of participants with instructional adjustments based on item analysis after each test being applied to one class, with no adjustment made for the other. Quantitative data measured student improvement (Mean and STD) and item analysis for each question allowed differentiation and the provision of DI where required (extension or corrective). Qualitative data were collected from students written reflections on their learning prior to and at the completion of each test. There were statistically significant differences between classes, with students indicating higher levels of self-efficacy and self-determination through mapping their own progress, identifying areas for improvement and through concrete evidence of progress in the class where data were used to adjust pedagogy. In addition to closing the education gap, implications include improved self-efficacy resulting in increased numbers in post compulsory music and improved teacher assessment and analysis skills.