Designing and constructing the written expression disorder test for the students of primary school

The aim of this study was to develop an expression disorder test for the students of the third, fourth, fifth and sixth grades of primary school. For this purpose, a test was designed and conducted in two stages of piloting and main phases. The sample consisted of 2403 students (1203 boys and 1200 girls) studying in the third, fourth, fifth and sixth grades. Participants were selected from four districts of Shiraz through multi-stage cluster sampling technique. The test’s psychometric properties were considered to check its reliability (open trial and Cronbach's alpha analysis) and validity (content validity was attested by the experts; correlation test was used to verify the criterion-reference validity while students’ means and their class distinction were considered to check the construct validity). The results, indicated that the developed test had an appropriate validity (both content and construct) and could be a useful assessing tool for the instructional applications for the written expression disorders at primary schools.