Entry #9: Variables

Well, that was exactly that came up into my mind when people started talking about variables. I was so confused as I often mixed up the definitions of dependent and independent variables. Then suddenly they came up with extraneous variables, manipulate variables, mediator variables, criterion variables and the list goes on and on. Pheww..

I realised that I really need to open the research methodology bible aka the 'handbook' written by Fraenkel, Wallen and Hyun (2012) and it is very much of help in understanding the elements in educational research.

Through my reading and lecture notes, I found that variable is actually a set of variation and it could be categorical or quantitative.

So what about the other variables mentioned earlier?
Well, to make it clearer to digest, based on my reading, I have concluded that:

independent variable = experimental variable = manipulated variable = treatment variable
dependent variable = criterion variable = outcome variable


What are the moderator, mediator and extraneous variables?

Extraneous variables
In previous entry, I have mentioned about the extraneous variables. The extraneous variables could influence the effect on the dependent variables or other variables that exist. Examples of extraneous variables are genders, the personality of teachers involved, the experience level of the students which could affect learning in the study. One of the way to avoid or control these variables is by holding them constant.

Moderator variables
It is a special type of independent variable. It is a secondary independent variable that has been selected for study to determine whether it affects or modifies the basic relationship between the primary independent variable and the dependent variable. The key word here is modify.

Mediator variables
It is one that attempts to explain the relationship between the two other variables. Mediator variables provide explanation to the relationship between the independent and dependent variables.

Below is the graphic organizer to explain the relationship between the variables.

The other factor could also be the extraneous, mediator or moderator variables.

Below are the examples for independent and dependent variables.

So I guess I won't get confuse anymore and whenever people ask me about variables, I hope I could explain them pretty well and same goes to answering the test :)