investigation of reliability, validity and normality persian version of

background: to evaluate the effectiveness of the present educational programs in terms of students' achieving problem solving, decision making and critical thinking skills, reliable, valid and standard instrument are needed. purposes: to investigate the reliability, validity and norm of cctst form.b         factor (element) namely: analysis, evaluation, lriference, inductive and deductive reasoning. internal consistency method shows that all subscales have been high and positive correlation with total test score. group difference method between nursing and philosophy students (n=50) indicated that there       is meaningful difference between nursing and philosophy students scores (t=-4.95,p=0.ooo1). scores percentile norm also show that percentile offifty scores related to   11 raw score and 95, 5 percentiles are related to 17 and 6 raw score ordinary. conclusions: the results revealed that the questions test is sufficiently reliable as a research tool, and all subscales measure a single construct (critical thinking) and are able to distinguished the persons with different level's ct.