Research studies that do not test specific relationships between variables are called descriptive studies. These methods are used to describe general or specific behaviors and attributes that are observed and measured. In the early stages of research it might be difficult to form a hypothesis, especially when there is not any existing literature in the area. In these situations designing an experiment would be premature, as the question of interest is not yet clearly defined as a hypothesis. Often a researcher will begin with a non-experimental approach, such as a descriptive study, to gain more information about the topic, before designing an experiment to address a hypothesis .
Descriptive research can be used to gain a vast, but often inconclusive, amount of information. It has the advantage of studying individuals in their natural environment without the influence of the artificial aspects of an experiment. This approach can also be used to document rare events or conditions that could not be reproduced in a laboratory.
One very important kind of descriptive research in psychology is the case study. A case study is an in-depth analysis of a person, group, or phenomenon. Case studies cannot be generalized to the overall population (as in an experiment) nor provide predictive power (as in correlational research). They do not allow researchers to identify cause and effect relationships, nor test hypotheses. They can, however, provide extensive information for the development of new hypotheses for future testing, and provide information about a rare or otherwise hard to study event or condition.
Case studies use techniques such as personal interviews, direct observation, psychometric tests, and archival records to gather information. They are often seen in clinical research, where the treatment of a specific individual is monitored to determine what is effective. For instance, a client in a mental health hospital could be studied as they progress through a course of treatment involving individual counseling, group therapy, and psychomedication. While any results from the study could only be applied to that particular client, the results could inform a future hypothesis about the relative effectiveness of such treatment options.