In February 2020, the Ministry of Education asked the New Zealand Council for Educational Research (NZCER) to examine the curriculum-levelling construct that sits at the heart of "The New Zealand Curriculum" (Ministry of Education, 2007) (NZC). A key goal of the research was to investigate, whether-- and if so, how--the construct helps (or hinders) teachers and school leaders as they plan learning programmes and make judgements of student progress and achievement. This study was prompted by earlier research examining curriculum levelling, which raised questions about the curriculum-levelling construct (Bonne & Hipkins, 2019). The current study examined relevant literature and documentation and involved interviews and focus group sessions with teachers, school leaders, professional learning and development (PLD) facilitators, and curriculum experts from around Aotearoa New Zealand. Interviews with two curriculum experts from Australia were also conducted. This report provides an overview of the findings from the study. The report is presented across six sections. The first section describes the curriculum-levelling construct. It outlines the study's guiding questions and presents the different methodological components that were used to investigate them. Section 2 looks at where the curriculum-levelling construct came from and how it has been presented over time. It discusses some of the factors that have informed its development. Section 3 looks at how the curriculum-levelling construct is interpreted by experienced leaders and classroom teachers in schools through their curriculum design decisions and their judgements about student progress and achievement in relation to curriculum levels. Section 4 examines the efficacy of the curriculum-levelling construct within today's curriculum and pedagogical environment. It discusses five issues that the research participants recognised as possible threats to the efficacy of the curriculum-levelling construct. Section 5 explores recent responses to the use of curriculum levels in England and New South Wales. It explains how decisions about the use of levels came to the fore during recent curriculum reviews in each of these places. The final section, Section 6, briefly summarises the research findings and looks at the future potential of curriculum levelling for supporting learning progression, learner progress, and an education system that learns. [For the summary report, see ED627146.]