Modeling relations between students’ justification for knowing beliefs in science, motivation for understanding what they read in science, and science achievement

•A path analysis approach was used with 122 lower-secondary school students.•Science reading comprehension self-efficacy predicted science achievement.•Effects of justification beliefs on achievement were mediated by self-efficacy.•Personal justification also had a direct negative effect on science achievement.•Justification by multiple sources had a direct positive effect on achievement. In this study, we generated and tested a hypothesized model that specified direct and indirect linkages between different types of beliefs concerning the justification for knowing in science, motivation for science reading comprehension, and science achievement. Using a path analysis approach with a sample of 122 lower-secondary school students, results indicated that students’ science reading comprehension self-efficacy predicted their achievement, with the justification belief variables indirectly affecting science achievement through their influence on science reading self-efficacy. Specifically, there was a negative indirect effect of personal justification on science achievement mediated by science reading comprehension self-efficacy, whereas both justification by authority and justification by multiple sources had positive indirect effects on science achievement mediated by self-efficacy. Beliefs in personal justification and justification by multiple sources affected achievement directly as well as indirectly. Both theoretical and educational implications of the results are discussed.