Social Research Glossary


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Citation reference: Harvey, L., 2012-20, Social Research Glossary, Quality Research International,

This is a dynamic glossary and the author would welcome any e-mail suggestions for additions or amendments. Page updated 19 December, 2019 , © Lee Harvey 2012–2020.


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core definition

An experiement is a procedures in which all the relevant variables are manipulaed by the experimenter in a controlled environment, which excludes any other variables that may effect the outcome.

explanatory context

The experiment is the exemplary methodological procedure in positivistic science. It is a study in which all the relevant variables are controlled and manipulated by the experimenter (so as to be able to specify causal relationships), rather than simply observed in their natural setting. This is the ‘ideal’ experiment. It is usually associated with the idea of a completely controlled environment, viz. a laboratory.


The approach, in this sense, is relatively rare in social science except in psychology (where it occurs in hybrid forms).


Other less formal and less structured approaches to experimen- tation include the field experiment and the quasi-experiment.


The experimental design is intended to ensure that an experiment affords a valid, efficient and unambiguous test of the hypotheses set up and that extraneous variables are controlled. Experimental designs range from the very simple to the very complex. A simple one would be to have just two levels of a single independent variable and test the effects on one dependent variable in two randomly chosen groups of people. Complex designs may entail having several independent variables, with matched groups, and/or repeated measures and/or statistical allowance for some of the extraneous variables, etc.


Experimental treatment is a systematic, carefully controlled change made by the experimenter in the environment of the experimental group, the aim of which is to test the predicted effects of the independent variable.


The experimental group is a group of people to whom the experimental treatment is given and who will be compared with a control group who have not received the experimental treatment.


This kind of approach is used widely in biology when investigating the effects of a treatment on animals or plants. It is less suited to humans because they are conscious of what is happening and are able to adjust their behaviour in order to compensate for the effect. As the ‘Hawthorne Experiments’ illustrated, it is not easy to separate the effect of the treatment from the changes in behaviour that have arisen as a result of the subjects being aware of the experimental situation.


Further, if the person conducting the experiment knows the experimental hypothesis there is always some danger that he or she may unconciously influence the results obtained in many small ways (tone of voice, extra encouragement etc.) in order to confirm the hypothesis. This is the experimenter bias effect. It may be guarded against in many ways-including using experimenters who do not know the hypothsis, and using research procedure which are clear and unambiguous and less amenable to such bias.

analytical review

Colorado State University (1993–2013) defines experiment as follows:

Experiment: Experimental Research A researcher working within this methodology creates an environment in which to observe and interpret the results of a research question. A key element in experimental research is that participants in a study are randomly assigned to groups. In an attempt to create a causal model (i.e., to discover the causal origin of a particular phenomenon), groups are treated differently and measurements are conducted to determine if different treatments appear to lead to different effects.


Elwell's Glossary of Sociology (undated) defines experiment as:

A research method in which variables can be analyzed under carefully controlled conditions--usually within an artificial situation constructed by the researcher.


Richard Schaefer (2017):

Experiment: An artificially created situation that allows the researcher to manipulate variables.


The NHS Health News Glossary, (NHS, undated) states:

Experiment: An experiment is any study in which the conditions are under the direct control of the researcher. This usually involves giving a group of people an intervention that wouldn't have occurred naturally. Experiments are often used to test the effects of a treatment in people, and usually involve comparison with a group who don't get the treatment.


associated issues


related areas

See also

field experiment


Researching the Real World Section 9


Colorado State University, 1993–2013, Glossary of Key Terms available at, accessed 1 February 2013, still available 3 June 2019.
Elwell's Glossary of Sociology, undated, available at, page not available 20 December 2016.

NHS, undated, Health News Glossary, available at, accessed 1 June 2019.

Schaefer, R. T., 2017, 'Glossary' in Sociology: A brief introduction, Fourth Edition, originally c. 2000, McGraw-Hill. Available at, site dated 2017, accessed 11 June 2017, 'not found' 3 June 2019.

copyright Lee Harvey 2012–2020


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