Testing validity inferences of science motivation questionnaire (SMQ-II) instrument: Rasch-based analysis with Indonesian secondary students

Examining science motivation is essential for science learning in the classroom, even more, science motivation is often related to students' achievement and performance. The test of science motivation has broadly employed and some of the instrument has been translated into a local language where the instrument used. The current study explores the validity evidence of Science Motivation Questionnaire II (SMQ-II) by IRT-Rasch based analysis using Test Analysis Models 'TAM' Package v. 3.1-45 in R software from Indonesian context. This study reveals construct validity of SMQ-II instrument based on The Standards for Educational and Psychological Testing using Messick's (1989) validity theories and construct validity. The data collected from 984 Indonesian middle and high school students. As result, the current study had SMQ-II validity evidence which includes (1) Dimensionality of the instrument using Exploratory Factor Analysis and Rasch-analysis likelihood ratio approach, (2) Expected A Posteriori (EAP) reliability and Weighted Maximum Likelihood Estimation (WLE) reliability, (3) Item fit and item properties, (4) Wright Map using Rasch modeling. The result of construct analysis shows that the instrument was appropriate with a theory where the construct was categorized into five dimensions, all the items of SMQ-II fit the rasch modelling, and the internal reliability of each dimension is categorized as good. In general, the current study suggests that SMQ-II instrument of Indonesian version is adequate to be implemented in Indonesia.