Institute of Educational

This study is aimed to evaluate the impact of Merrill instructional design model and ADDIE in learning and retention epidemiology of medical Science University of Tehran in academic year 2013-2014. The study method is experimental. The total population is 98 as divided randomly to three classes 30 people to do three instructional methods (Merrill, ADDIE and traditional). A researcher-built academic progress test is used in the study. The data are analyzed by descriptive statistics and inference statistics (t-test) and the results of study were as follows: The learning and retention of the studies receiving Merrill and ADDIE instructional design models were more than the students trained by common classroom method. Deterioration of retention in instruction via two experiment group models is less than traditional method. There was no significant difference between learning and retention with two design models.