Analogous to the other 71 countries/economies participating in Programme for International Student Assessment (PISA) 2015 Study, after the release of the sampled survey data at end of 2016, Macao government is eager to know the most important issues and the associated factors that have a bearing on the quality and equity of its basic education system in the fostering of scientific literacy performance. Included in the student, parent, school and system-level questionnaires are hundreds of variables conceptualized in accordance with the context assessment framework. These variables are hypothesized to explain performance variance both within and across economies participating in PISA 2015. For informed policy making, important issues and the associated factors which have a bearing on the classification of high- and low-performing students in scientific literacy have to be sought. This study adopts a Classification and Regression Trees (CART) approach to handle the complexity of the assessment data with different levels of measurement and distributional properties. The findings highlight a number of important variables, i.e. grade repetition, weekly learning time, environmental awareness and epistemic beliefs. These variables are needed in-depth examination in order to formulate educational policies and intervention studies that are specific to the fostering of scientific literacy in the Macao schooling contexts.