Diagnostic tests are useful in finding out the strength and weaknesses of the individuals. They help in designing courses and curriculum according to the capabilities of the learner to help him overcome his deficiencies in knowledge skills and abilities and to assist him in making the best use of his potentialities. This helps find out the causes of problems that remain unchecked and unremedied by formative evaluation. The tests are useful to both the attainment as well as difficulties of children whose achievements are not up to the mark. This helps locate the areas in which additional instruction is required or in which the teaching method has to be improved.