Several different scientific methods are used in psychology, each with its own advantages and disadvantages. Different methods are best suited to answer different types of questions, so they tend to be related to different degrees by individual methods of scientific inquiry that involve description. (Benjamin B. Lohey)

In everyday life, we all observe and describe people, often drawing conclusions about why they behave as they do. Professional psychologists do more or less the same thing, just in a more objective and systematic way. (David Myers, 2001)

Research methods have been classified in many different ways. A simple approach that is widely used distinguishes between four main strategies; case study, survey, experiment, naturalistic observations.

Case study is a psychological study that involves the detailed investigation of a single particular case or individual. (Peter Stratton and Nicky Hayes, 1988). The individual as a case is probably the first thing that comes to mind. Case studies are not necessarily studies of individuals, although they can be done about a group, an institution, a neighborhood, an innovation, a decision, a service, a program, and many other things.

The case studies are therefore very varied. We have individual case studies, individual case studies, community studies, social group studies, organization studies, institutions, and event, role, and relationship studies. (Colin Robson, 1993)

The term Survey is used in various ways, but commonly refers to the collection of standardized information from a specific population, or some sample of one, usually, but not necessarily, by means of a questionnaire or interview. In general, a relatively small amount of information is collected from any one individual, building on a case study, where a large amount of information can be obtained from ‘a key informant’. Surveys are good for descriptive studies where the interest is, say; how many people in a given population possess a particular attribute, opinion, or whatever. However, survey data can also be used to explore aspects of a situation or to seek an explanation and provide data to test hypotheses. (Colin Robson, 1993)

The Experimental Method is the most disciplined of the methodologies used by psychologists. Using these methods, an experimenter manipulates a variable to be studied, chooses the response to be measured, and controls for extraneous or irrelevant influences that might inappropriately affect the results of the experiment.

Information collected in this way is called research information. Properly conducted research satisfies several criteria, such as an objective, systematic, repeatable, empirical, public, and significant problem. (Wittig and Becklin, 1977)

Naturalistic observation is the careful observation of events not manipulated by the observer. Like case study and survey methods, naturalistic observation does not explain behavior. describes it. (David G. Myers, 2001) For example: a psychologist interested in studying children’s play might observe several children together in a playroom. Using a one-way mirror, the psychologist could then observe and record the child’s activity without her being noticed. In this way, the psychologist could minimize the influence that an ‘adult presence’ could have on the children. Children can do what they want, unless for some reason the psychologist stops their game. (Wittig and Belkin, 1977)

Sociologists also use the terms I mentioned above to study their different research on society and social patterns among individuals.

The differences are not many:

Since the survey involves a study of a sample of the population under study. A researcher can estimate the opinions and attitudes of the largest population bases on data obtained systematically from a selected sample by extrapolating their findings.

Experiments: test the cause and effect relationships between two variables. The three basic steps characterize most sociological experimentation.

Establishment of two comparable groups: experimental and control groups
· Expose the experimental group to some influence, stimulus or conditioning.

Observation: Observation of social behavior in natural environments. The researcher tries to become part of the group.

Case histories: allow for deeper exploration of issues (eg, involve examination of behavior, feelings, thoughts, etc.) (LA Coser, SL Nock, PA Steffan, D. Spain, 1991)

There are several advantages and disadvantages that concern these psychological methods in psychology.

Survey: Collection of information in a standardized form from groups of people.


a) The data is affected by the characteristics of the respondents.
b) Respondents will not necessarily report their beliefs, attitudes, etc.
c) They typically have a low response rate.
d) Ambiguities and misunderstandings in the survey questions may not be detected.
e) Respondents cannot treat exercise seriously.


a) They provide a relatively simple and forced approach to the study of attitudes, values, etc.
b) They can be adapted to collect generalizable information from almost any human population.
c) Highly structured surveys have a large amount of data standardization.
d) The easiest way to retrieve information about the history of the greatest people.
e) Extremely efficient to provide large amounts of data, at a relatively low cost in a short period of time. Although this may coincide as disadvantages, they do entice the researcher to use the survey when it may not be the most appropriate strategy to answer the research questions. (Colin Robson, 1993)

Experiment measuring the effects of manipulating one variable on another variable.


Random Assignment: There are practical and ethical problems in achieving random assignments to different treatments or experimental conditions. Random is also feasible in typical circumstances or with selected respondents leading to questionable generalization.

Validity: The actual treatment may be an imperfect realization of the variables of interest, or a restricted range of results may be insensitive and result in questionable validity.

Ethical issues: strict compliance with ethical guidelines is advocated, but this can lead to missing some as the advantages of using common sense are needed.

Control: the output variables may mask the effects of the treatment variables or bias their evaluation.


Generalization: if it is about generalization results to the real world, the task is easier if it is about experiments in a natural environment.

Validity: The demanding characteristics of laboratory experiments in which subjects tend to do what you want them to do are enhanced by the artificiality and isolation of the laboratory situation.

Availability of Subjects: Getting subjects to come to the lab is not an easy task. You have to trust them to show up. (Colin Robson, 1993)

Case study: development of detailed intensive knowledge about a single case or a small number of relative cases.

Selection of a single case of a situation, individual or group or interest or concern; Study of a place in its context. Collection of information through a variety of data collection techniques including observation, interview, and documentary analysis.

Naturalistic Observation: One problem is that many observational studies are the effect of the observer on the behaviors of the subjects. If the presence of the observers profoundly affects the action of the subjects, the study might not be successful in testing the validity of the hypothesis. When concealment is impossible, the observer tries to blend into the background and refrains from reporting any behavior until his presence is taken for granted. (RR Bootzin, GHBover, Robert BZ, E. Hall, 1975)

All of the above methods I mentioned are useful as they serve different purposes:

Experiments for explanatory studies
Survey for descriptive studies
Case study for exploratory purposes
And, Naturalistic Observations for Individual Societies, Beliefs and Thoughts.