What are independent, dependent, and control variables?
In experimental research, the researcher wants to know what the effect would be if something were changed. Everything that could be changed and measured is called a variable.
To understand this, read the following example:
Think about how you can cook rice on an open flame. What do you need to ensure so that the rice is not mushy?
These are some potential variables for this example:
- type of rice
- strength of the flame
- amount of water
- taste of the rice
- softness of the rice
- cooking time
- times the rice was rinsed
- and many more
Everything in the list above can be measured and can change, which is why they are all variables. However, some of them are variables you can directly set, such as:
- type of rice
- strength of the flame
- amount of water
- cooking time
- times the rice was rinsed
and when you alter the above variables, there are other variables that can change, such as:
- taste of the rice
- softness of the rice
All variables that you can control the conditions for are called independent variables. All variables that change as a consequence of the changing independent variables are called dependent variables.
For example, you can control the amount of water and the cooking time to know their effect on the softness of the rice. The independent variables are the amount of water and cooking time, and the dependent variable is the softness of the rice. This is one example of experimental research. The goal of experimental research is to describe the relationship between independent and dependent variables.
In this example, even if there are two independent variables that you are interested in studying, there are still possible effects on the dependent variable arising from other variables (strength of the flame, etc.). If you are not interested in the effects of these other variables, you need to make sure that they are held constant. Variables that are held constant are called control variables.
If you will not control these other variables, there is a possibility that the dependent variable will also change uncontrollably. Therefore, your description of the effect of the independent variables on the dependent variable will be incorrect.
REMEMBER:
A variable is something in an experiment that can be measured and can change.
An independent variable is what is being directly changed.
A dependent variable can change because of changes in the independent variables. It is possible that the independent and control variables do not affect the dependent variable.
Control variables are potential independent variables that are unchanged because the researcher has no interest in knowing their effect on the dependent variable.
Tanim Talino 