3) Greater Accuracy: In other methods like interview, questionnaire etc., the researcher has to depend on information provided by the respondents. So these are indirect methods and here the investigator does not have any means to examine the accuracy of the data supplied by them. But in observation the observer can directly check the accuracy from the observed. He can apply various devices to test the reliability of their behaviour. So very often the data collected through observation is more reliable than these collected through interview or questionnaire. (4) An Universal Method: Observation is a common method used in all sciences, whether physical or social. So it has greater universality of practice. As a common method, it is very easily followed and accepted