What is A Variable?

                      What is A Variable?

                                                  Written by Ari Julianto


I. The Meaning
      A variable is any entity that can take on different values. So what does that mean? Anything that can vary can be considered a variable. Arikunto (1999) stated that variable is an object of research or waht is the target in a research.For instance, age can be considered a variable because age can take different values for different people or for the same person at different times. Similarly, country can be considered a variable because a person's country can be assigned a value.
      A variable is a concept or abstract idea that can be described in measurable terms. In research, this term refers to the measurable characteristics, qualities, traits, or attributes of a particular individual, object, or situation being studied.
      Variables are properties or characteristics of some event, object, or person that can take on different values or amounts. Variables are things that we measure, control, or manipulate in research. They differ in many respects, most notably in the role they are given in our research and in the type of measures that can be applied to them. By itself, the statement of the problem usually provides only general direction for the research study; it does not include all the specific information.

II. Types of Variables
      There are many classification systems given in the literature the names we use are descriptive; they describe the roles that variables play in a research study. The variables described below by no means exhaust the different systems and names that exist, but they are the most useful for communicating about educational research.

1. Independent variables
      Independent variables are variables which are manipulated or controlled or changed. In the example “a study of the effect of teacher praise on the reading achievement of second-graders”, the effect of praise, the researcher is trying to determine whether there is a cause-and-effect relationship, so the kind of praise is varied to see whether it produces different scores on the reading achievement test. We call this a manipulated independent variable (treatment variable). The amount and kind of praise is manipulated by the researcher.
      The researcher could analyze the scores for boys and girls separately to see whether the results are the same for both genders. In this case gender s a classifying or attributes independent variable. The researcher cannot manipulate gender, but can classify the children according to gender.

2 Dependent variables
      Dependent variables are the outcome variables and are the variables for which we calculate statistics. The variable which hangs on account of independent variable is known as dependent variable. Let us take the example, a study of the effect of teacher praise on the reading achievement of second-graders; the dependent variable is reading achievement.
      We might compare the average reading achievement scores of second-graders in different praise conditions such as no praise, oral praise, written praise, and combined oral and written praise. Some other variables are expected to be "dependent" on the manipulation or experimental conditions. That is to say, they depend on "what the subject will do" in response.
      Somewhat contrary to the nature of this distinction, these terms are also used in studies where we do not literally manipulate independent variables, but only assign subjects to "experimental groups" based on some pre-existing properties of the subjects.
      Independent variables are those that are manipulated whereas dependent variables are only measured or registered. Consider other examples of independent and dependent variables:

3. Extraneous variable
      Independent variables that are not related to the purpose of the study, but may affect the dependent variable are termed as extraneous variables. Suppose the researcher wants to test the hypothesis that there is a relationship between children’s gains in social studies achievement and their self-concepts. In this case self-concept is an independent variable and social studies achievement is a dependent variable.
      Intelligence may as well affect the social studies achievement, but since it is not related to the purpose of the study undertaken by the researcher, it will be termed as an extraneous variable. Whatever effect is noticed on dependent variable as a result of extraneous variable(s) is technically described as an ‘experimental error’. A study must always be so designed that the effect upon the dependent variable is attributed entirely to the independent variable(s), and not to some extraneous variable or variables.

4 Intervening variables
      They intervene between cause and effect. It is difficult to observe, as they are related with individuals feelings such as boredom, fatigue excitement At times some of these variables cannot be controlled or measured but have an important effect upon the result of the study as it intervenes between cause and effect. Though difficult, it has to be controlled through appropriate design.

5 Moderator
      A moderator variable is an independent variable that is not of primary interest that has levels, which when combined with the levels of the independent variable of interest produces different effects.

(Taken from various sources)