Gauging Interaction in Situated Expectancy-Value Theory: an Investigation into the Relative Importance and Mutual Moderation Between Reading Enjoyment and Self-Concept in Predicting Reading Achievement

According to the situated expectancy-value theory (SEVT), reading achievement can be driven by two key motivational factors (expectancy and task value) and the interaction between them. Existing studies on reading have mostly focused on the main effects at the expense of insufficient attention to interaction. Besides, interaction has merely been operationalized as the product term between expectancy and value (i.e., expectancy multiplying value, Type 1 interaction), neglecting the relative (or comparative) importance of expectancy and value (i.e., the competition between them, Type 2 interaction) in determining reading achievement. To address these gaps, the current study examined the main effects of and the two types of interaction between two expectancy-value factors, namely, reading enjoyment (indicating value) and self-concept (indicating expectancy), in predicting reading achievement. We used the Program for International Student Assessment (PISA) 2018 data generated by 532,835 students (Mean age = 15.79, SD = 0.29, 51