This study aimed to develop a multitier instrument of fluids concepts (MIFO) using Rasch analysis.
The research method as utilized the ADDIE model. Participants were 103 students (47male and 56female), and
their average age was 16-17 years old, at one of senior high school in Bandung, West Java, Indonesia.The
MIFO consists of 12 items in form of four-tier test. MIFO examined through Rasch analysis based onitemperson maps of student's conception, unidimensionality, fit statistic, item-person separation, reliability,and
differential item functioning. Student's conceptions were categorized as scientific conception, lack of
knowledge, and misconception. The outcomes of a Rasch analysis revealed how the evaluation analysis offered
dataintended for assessingthe student's conception of fluids concepts. Then it can be concluded that the MIFO
can be developed to measure student's conception. This study can be a reference for educators or teachers
forfurther study and prepare tests to identify student's conceptions.