Experimental Research

Experimental Research is used specifically to test causal relationships. It involves the researcher maintaining control over all factors that may influence the result of a research experiment, in an attempt to find out what variables ‘cause’ a certain ‘effect’. It involves the researcher designing an experiment whereby all variables that may influence a certain effect can be controled or manipulated. In this situation, the research is then able to study certain independent variables and study the effect that they cause on dependent variables. This method is particularly useful at testing cause-effect hypothesis, as it enables researchers to eliminate various possible and alternative hypotheses. There are various ways in which experimental research may be desinged. Some of the key designs are:

The Basic Design

(Also known as the Post-test-Only Control Group Design).

This involves the random assignment of participants to one of two different groups that will both undergo different ‘treatments’. This allows comparisons to be drawn on the responses of each of the two groups to the treatment or cause that may be under study.

The Basic Pre-test Design

This involves adding a pre-test measure to the basic design, thus allowing the researcher to measure ‘how much’ change occurs in participants undergoing ‘treatments’ under a basic design experiment.

The Solomon Four Group Design

This involves the random assignment of participants to four groups (instead of two as prescribed in the basic design.) It is used in order to determine whether or not the testing treatment has occurred, and also asses the extent to which it has impacted on the test groups.

Factorial Design

This is used for experiments that include more than one independent variable under study. It requires a number of test groups equivalent to all possible combinations of the presence or non-presence of the various variables.

Repeated Measures Design

(Also known as ‘within subject’)