There are a variety of methods used when studying child development, these are: experimental, correlational, naturalistic observation, surveys, and case studies.
The most notable and often used by psychologists and scientists is that of the experimental method, as due to the controlled environment, the outcome is unaffected by possible interference were the same components being studied were observed in its natural environment. However, this method does have its disadvantages, one of which is that real life behavior is often not a result of just one variable, but it is often affected by many influences, and thus giving one variable all the credit or blame for a behavior may be inaccurate.
Correlational studies are used to determine the relationship between two events or two points of interest using scattergrams to chart out correlation. The disadvantage to this method is that no matter how strong a relationship between two points of interest, we can not be certain that one point is causing the other, as we can be with the experimental method, where all variables are controlled.
In naturalistic observational studies, psychologists observe a patient or subject in its natural environment. For example, if the subject is a child, then the child would be observed while in the nursery, or at a playground, interacting with other children, etc. Studies that are based on naturalistic observation have their drawbacks in the form of observer or subject bias—observer bias in that no person will view one situation or behavior in the same way as another, and subject bias in that if a child thinks he is being observed, then he may behave differently than if he thought he was alone. Also, as with correlational studies, we cannot know for certain (solely through naturalistic observation) what causes the behavior being observed.
Surveys are a means of gathering information through questionnaires or interviews. This method has its advantages in taking large random samplings from a population with less effort than if any other method of study were used. The disadvantage to surveys is that it relies on the subject’s accurate and honest recall of past behavior, which may not always be an accurate depiction of what has taken place.
Case studies are the intense and thorough study of one subject, this type of methodology has been used by Freud to substantiate various of his theories. The disadvantage to case studies is that it is difficult to generalize one’s findings from one subject to a larger populace.