Inventori Konsep Daya is an instrument that is adapted from the Force Concept Inventory (FCI). It is an instrument consisting of 30 diagnostic items related to the concept of force and motion. This instrument is widely used in physics education. However, the validity of this instrument in Bahasa Malaysia is not well studied to ensure that the items in the instrument function properly. Based on previous research, one of the major issues that are often questioned in the FCI is the reliability of the instrument when administered to different groups. When studies conducted in this country, researchers often use the reliability analysis under the Classical Test Theory. Various weaknesses are identified when evaluating using the analysis under the theory. Therefore, the purpose of this study is to apply the Rasch model under Item Response Theory in analyzing the items in Inventori Konsep Daya. Several analyzes were selected to determine the validity of the items and instruments. This study will be conducted on three levels of students involved in the learning of force and motion concepts. 300 samples will be taken from school students, elementary or matriculation students as well as undergraduate students who have studied this topic. The data will be analyzed using Windstep software. The results showed that Inventori Konsep Daya was a good instrument with high reliability and separation index, positive polarity value for every item, and fit the Rasch model. However, the instrument was quite difficult for the respondents in this study. This study is important in providing information to other researchers who will use FCI as an instrument in their study. In addition, the findings of this study can also be used to compare with the previous studies to draw more accurate conclusions.