Experimental Research

1.  What is Experimental Research?

Most of researchers related to science subjects such as sociology, psychology, physics, chemistry, biology and medicine etc., use Experimental research methods to conduct research.

In the experimental research the researcher examines the effect of independent variable on the dependent variable. the researcher observes the effects of controlled conditions and non-controlled conditions on group of people.

In psychology Experimental research is used to determine people behavior and mental processes. It also effects of independent variables on dependent variables in controlled environment. Moreover, experimental research can determine a cause and effect relationship between two variables. However, the effects of a controlled environment could not be eliminated.

2. When did the researchers use Experimental Research?

The researchers use Experimental Research when Time priority is priority to find out causal relationship or causal relationship is found with consistency or degree of the correlation is great.

There are three major types of design

1. True-Experimental Research Design

2. Quasi-Experimental Research Design

3. Pre-Experimental Research Design


In true experimental design the researcher selects the subjects randomly. Then researcher makes control groups and assigns assignments to the control and experimental groups randomly.

When researcher decides to do an experiment follows a true-experimental design, researcher sets a preceding criterion. The researcher decides how many times that treatment is given to the experimental group. If there is any pre-test, post-test, mid-test etc. What will be its duration? true-experimental design always has greater internal validity.


Quasi-experimental design is basically related to constructions that already exist in the real world. A quasi-experimental design also has controlled and experimental groups, but the researcher did not select groups randomly. It has greater external validity


In pre-experimental design researcher did not select group randomly. Researcher experiments on one group. There is no separation of controlled and non-controlled group. Pre-experimental design has lower validity.