In Australia, it has been observed that there have been significant declines in the proportion of students studying senior sciences over the last two decades (Commonwealth of Australia 2017 & 2018; Steidtmann et.al, 2023). It has been suggested that one of the causes for this decline could be a link between students' literacy achievement and their engagement with the demanding reasoning processes in science that affect student pathways into senior secondary science (Cooper et.al, 2022). In recognising the importance of critical and creative thinking and the current context of Australia, this longitudinal study explores the effect of cognitive acceleration in science education (CASE) in 12- and 13-year-olds of a K-12 college in a middle socio-economic suburb of Western Australia over a period of six years to determine its impact on students' NAPLAN (Year 7 and 9) and ATAR (Year 12) performance. The cognitive gains through the CASE intervention are examined in the light of student achievements upon completion of WACE (Western Australian Certificate of Education). Teachers implementing CASE in the science classrooms participated in a two-year professional development, and as such, this study also cast some light on how their teaching practices have been influenced or shaped by their experience of delivering the CASE intervention.