Different methodologies are used in order to decipher the negative relationship described in Volume II of the PISA 2015 initial report (OECD, 2016b). They explore the interactions between enquiry-based teaching and the school environment, differences in the benefits of such teaching practices, depending on student proficiency in science (e.g. top performers might benefit more from scientific enquiry) and on the branch of science being taught (e.g. chemistry, biology), and whether enquiry is more useful in helping students engage with more difficult science tasks. The question asked about the frequency with which certain enquiry-based practices are undertaken in science classes. Answers were provided on a four-point Likert scale ranging from “In all lessons”, “In most lessons”, “In some lessons”, to “Never or hardly ever”.