This research is a development and measurement research. This research is conducted to develop a good instrument in measuring elementary school students’ skill by IRT approach which based on; 1) validity and reliability of instrument; 2) assumption test; unidimensional, local independence and parameter invariance; 3) characteristics of item test and 4) measuring students’ ability. This research is developed by the development model of DjemariMardapi, such as: 1) arranging test specification, 2) writing the test, 3) examining the test, 4) conducting trial test, 5) analyzing the item test, 6) improving the test, 7) assembling the test, 8) implementing the test and 9) interpreting the result of test. The research founding; 1) the range of aiken value developed for instrument test of grade 3 is 0.83-1. While the reliability coefficient of instrument test of math skill in grade 3 is 0.883. the result indicates that the item test developed has good validity and reliability. 2) unidimensional test is fulfilled since the test is proven only measure one dominant dimension i.e., the same skill. The assumption test of local independence is also fulfilled due to the value of covariant among interval of skill is small or close to zero. The calculation result between difficulty level from response includes in high category, therefore the assumption of parameter invariance of skill is fulfilled; 3) based on analysis of the three instruments of fit model result, it fits on 2Pl model, so on the parameter estimation of the item, overall package estimates on 2PL model or parameter b and a (difficulty level and trick). Based on the analysis result of parameter item test in grade 3 indicates that the overall item is on good categories of difficulty level and trick; 4) the measurement of students’ skill indicates that the average of students’ skill is 0.451 with the maximum skill score of students is 3.185 and the minimum students’ skill is -2.282. if it is observed from students’ average score, students in the research samples have good average of math skill.
Mathematics Test Development By Item Response Theory Approach And Its Measrument On Elementary School Students
