Quantitative Research Designs

The formal experiment and manipulation of variables

The experiment represents the only way in which researchers can definitively establish cause-and-effect relationships.

In a formal experimental design, the practitioner investigates the link between two or more factors by deliberately altering one of them in a strictly controlled situation to observe what impact that change has on other aspects. This intentional modification is known as experimental manipulation.

To ensure validity, it is essential to compare the responses of at least two groups: the experimental group, which receives the specific treatment or change, and the control group, which receives no or a different modification.

This contrast makes it possible to ensure that any variation detected is a direct consequence of the researcher's intervention and not the product of unforeseen external factors.

Difference between dependent and independent variable

A crucial element in quantitative designs is the correct identification of the variables involved.

The independent variable is the condition that the experimenter manipulates at will; it is considered the "cause" and its value is autonomous with respect to the actions of the participants.

In contrast, the dependent variable is that which is measured to observe the effects of the manipulation; it represents the "effect" and is expected to change as a direct result of alterations made to the independent variable.

For example, if a company wishes to test a new training system, the educational program would be the independent variable, while the subsequent productivity level of employees would be the dependent variable.

Only if the cause is manipulated and the effect is measured under a procedure of random assignment to groups can one speak of a true experiment.

Summary

The formal experiment is the only way to establish definitive cause and effect relationships. It requires the deliberate manipulation of one independent variable to observe its impact on another.

It is essential to compare an experimental group, which receives the treatment, with a control group. This contrast ensures that the variations detected are a direct consequence of the intervention carried out.

The independent variable represents the manipulated cause, while the dependent variable is the measured effect. Only through randomized procedures can a true experiment be validated in the organization.