Psychometric properties of school readiness test of first Step according to Item Response Theory

The present study was conducted to evaluate the psychometric properties of school readiness test ofFIRST STEP in Guilan province, according to Item Response Theory. For this purpose, a sample of 1500 subjects was selected randomly from all the students who participated in the program of physical health and school readiness in Guilan province in 2012-2013 , and the data obtained from the implementation of the test on this sample group, collected and used for statistical analysis according to Item Response Theory . Initially , Unidimensionality and Local Independence were investigated using the NOHARM program , which showed that the test was Unidimensionality and consequently , its Local Independence . Then , to estimate the best model - data for this test , according to Item Response Theory and using the statistical analysis program BILOG . MG , the necessary analysis was done on the data . Finally , the results indicated that the two - parametermodelhad a better fit with the test . In the next step , the parameters of the questionnaire in the two - parameter model ( Item Difficulty and the Discriminating Power ) as well as the ability parameters of the subjects were extracted and it was determined that the average difficulty of the questions was - 2.93 , indicating easy questions . The Item Information Functiontest diagram also indicated that the most awareness of this test was -3 in abilities , and this means that most of the questions in this test are suitable for people with low abilities . In analyzing the Differential Item Functioning based on different groups of gender , residence , having a nursery history and the age of the novices , the analyzes were done using the BILOG . MG statistical analysis program , shows that this test has a bias towards these groupings and these factors have a significant impact on the respondentchr('39')s responses to the test questions .