Indonesia's PISA reading score fell to ۳۵۹ in ۲۰۲۲, reflecting ongoing reading literacy. However, few studies have validated digital reading tests for elementary students. This study aims to analyze the validity of digital reading literacy assessments integrated into digital children's literature textbooks for elementary school students. The digital reading literacy instrument was developed based on the PISA and the Progress in International Reading Literacy Study (PIRLS), encompassing dimensions of comprehension, interpretation, reflection, evaluation, reading engagement, and digital literacy. The assessment focused on Indonesian reading literacy in a multilingual elementary school context. Using an explanatory sequential mixed-methods design, the study involved ۶۲ students for quantitative testing and ۱۰ teachers for qualitative interviews across six elementary schools in Banyumas Regency, Indonesia, where Banyumasan Javanese is the native language, and Indonesian is used for instruction and assessment. Content validity is assessed through expert judgment. Statistical validity testing using corrected item-total correlations indicates that ۲۰ of ۲۵ items meet the validity criteria. Reliability testing using Cronbach’s Alpha indicates high internal consistency. This instrument was implemented through a digital children's literature textbook featuring multimodal components. Quantitative data were collected through pre- and post-tests to measure changes in literacy assessment scores, revealing a significant improvement in students’ reading literacy assessment performance, with a very large practical effect. Qualitative insights from semi-structured interviews with teachers and students indicated enhanced student engagement, comprehension, increased vocabulary acquisition, and deeper emotional and cultural connections to the texts. Overall, the results show that using reading literacy assessments in digital children's textbooks provides a valid, reliable way to evaluate elementary students’ reading skills in digital learning settings.
