VARIABLES

A variable is any entity that can take on different values. Anything that can vary can be considered a variable. For instance, age can be considered a variable because age can take different values for different people. Salary can be considered to be a variable, as different people earn different salaries.

Variables aren't always 'quantitative' or numerical. The variable 'gender' consists of two text values: 'male' and 'female'. ‘Newspaper preference’ is also a variable. One person might prefer reading ‘The Times of India’ while another might like to read ‘DNA’.

Eg. In the research question : “Do highly-educated people read more number of newspapers than lesser-educated people?”, the two variables are Education level (which can take the value of either ‘Highly Educated’ or ‘Lesser Educated’) and ‘Number of newspapers read’.

In the above research, the number of newspapers you read depends on your education level. Therefore ‘number of newspapers’ is the dependent variable(DV). And ‘Education level’ is the independent variable(IV).

Similarly in the research question : Does ‘The Times of India’ give more coverage to entertainment news than ‘The Hindustan Times’, the two variables are Newspaper (which can be either ‘The Times of India’ or ‘The Hindustan Times’) and ‘The Coverage given to Entertainment News’.  The coverage given to the entertainment news may be more for ‘The Times of India’ and less for ‘The Hindustan Times’. Thus, the coverage to entertainment news depends on the Newspaper. Thus, ‘Coverage to Entertainment news’ and is the Dependent Variable(DV), and ‘Newspaper’ is the Independent Variable(IV).

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Extraneous Variables :

Extraneous Variables are variables other than the Independent Variable that might affect the Dependent Variable.

Eg.  In the research question : “Do highly-educated people read more number of newspapers than lesser-educated people?”, The DV ‘Number of Newspapers read’ might also be dependent on the age, the nature, the intelligence of the person etc. However, the researcher may not be able to measure these variables, although they might influence the DV.

These variables, which can also affect the Dependent Variable, but cannot be controlled by the researcher are known as Extraneous Variables.

 

Control Variables

If the researcher does not want an Extraneous Variable to affect the Dependent Variable, he has to control it, and it becomes a Control Variable.

Usually, a variable is controlled by keeping its value constant. Eg. In the above research, if the researcher does not want the variable ‘Age’ to influence ‘Number of Newspapers read’, he can make sure that all subjects are of the same age. The only thing that will be differing will be their from person to person will be his Education level. The age of all the subjects will be the same, to make sure age does not influence the DV.

 

Two kinds of IVs

Attribute IV :  Attribute IVs are usually attributes of people. Eg. Age, Gender, Salary, etc. An Attribute IV is an IV which is beyond the control of a researcher and he cannot change it as per his will during the IV.

Eg. If the age of a person is 20, the researcher cannot change it to 30 or 40.

 

Active IV :  Active IVs can be changed or controlled by the researcher.

Eg. Anxiety level of a person, the researcher can make a person more anxious or less anxious.

Type of medicine administered in a medical experiment (which can be changed by the researcher) etc.