Development and Validation of Respiratory and Circulatory System Achievement Test Using Rasch Model: A PISA-Compliant Instrument

Abstract

The development of the Respiratory and Circulatory System Achievement Test (ReCSAT) was inspired by the concerning results of Filipino students in a recent international assessment, where their performance in creative thinking scored below the global average. This outcome highlighted the urgent need for reliable, standards-based assessment tools that align with international frameworks. In response to this need, the researcher aimed to develop and validate the ReCSAT, which is a 30-item assessment tool designed in alignment with the Programme for International Student Assessment (PISA) 2025 Science Framework. Expert evaluations confirmed its alignment, with an overall rating of 4.72, indicating that the experts “strongly agree” that ReCSAT is a PISA-compliant assessment instrument. The abovementioned assessment tool was designed to measure Grade 9 students’ conceptual understanding, problem-solving, and creative thinking skills in specific science concepts: Respiratory and Circulatory Systems. The validation process employed a quantitative analysis. Content validity was proven through experts' evaluation, wherein the ReCSAT’s Fleiss Kappa value of 0.91 shows “almost perfect” agreement among the raters. Additionally, the construct validity was assessed using the Rasch Model, affirming the test’s unidimensionality and local independence of the items. The assessment tool also showed a balanced range in item difficulty and item discrimination, with a 0.90 Person Separation Index and four distinct strata revealing ReCSAT’s ability to distinguish four varied proficiency levels. The analysis in Differential Item Functioning demonstrates that the majority of the test items are fair for both male and female group. The ReCSAT was proven to be valid, reliable, and PISA-compliant instrument that measures students’ understanding in Respiratory and Circulatory System. This research recommends the integration of ReCSAT in classroom assessment and future studies about the examination of scientific literacy in Biology.