Experimental Research
A scientific investigation in which the researcher manipulates one or more independent variables, controls any other relevant variables, and observes the effect of the manipulations on the dependent variable(s). (Donald Ari, 2010)
An experimenter systematically introduces change and observes the consequences of that change. Only research problems that permit a researcher to manipulate conditions are appropriate for experimental research. The goal of experimental research is to determine whether a causal relationship exists between two or more variables.
The basis of the experimental method is the experiment, which can be defined as: a test under controlled conditions that is made to demonstrate a known truth or examine the validity of a hypothesis. (Daniel Muijs, 2004)
When doing an experiment we want to control the environment as much as possible and only concentrate on those variables that we want to study. Control is also increased by the fact that in an experiment the researcher manipulates the variable that is supposed to affect the outcome of the experiment.
Experimental research is the description and analysis of what will be or what will occur, under carefully controlled condition. (John Best in Yogest, 2006)
Experimental method is a scientific method. It is oriented to the future in the sense that the researcher is seeking to evaluate something new. It is a process of contribution to the already acquired fund of knowledge.
Characteristics of experimental research
Control; refers to removing or minimizing the influence of such variables by several methods
Control of variables is the essence of experimental method. When a study is completed, researchers want to attribute the outcome to the experimental treatment. To do this, they must eliminate all other possible explanations by controlling the influence of irrelevant variables. Without control it is impossible to evaluate unambiguously the effects of an independent variable or to make inferences about causality. The purpose of control in an experiment is to arrange a situation in which the effect of a manipulated variable on a dependent variable can be investigated.
Manipulation; refers to a deliberate operation of the conditions by the researcher.
The manipulation of an independent variable is a deliberate operation performed by the experimenter. In educational research and other behavioral sciences, the manipulation of an independent variable involves setting up different treatment conditions. Treatment is another word for the experimental manipulation of the independent variable. The different treatment conditions administered to the subjects in the experiment are the levels of the independent variable. Independent variables, such as different teaching methods (lecture versus discussion) or different instructions given to subjects, have levels differing in kind. A researcher may manipulate more than one independent variable in a single study.
Observation and measurement
After applying the experimental treatment, the researcher observes to determine if the hypothesized change has occurred. Some changes can be observed directly, whereas other changes are measured indirectly. Learning, for example, is often the dependent variable in educational research. Researchers cannot measure learning directly. They can only estimate learning through scores on an achievement test or other measures chosen according to the operational definition.
