Quant #11: Types of Variables

In quantitative research, the analysis to be conducted heavily depends upon the nature of the variables to be used. The most commonly used classification of variables consists of dichotomous, categorical, and continuous variables. Usually, dichotomous and categorical variables are subsumed under a class known as discrete variables.

Dichotomous variables refer to variables that can only have two possible response categories. For example, a variable whose possible response categories are "Yes" and "No" – coded 1 and 0, respectively – can be construed as a dichotomous variable. Dichotomous variables can also be referred to as binary variables.

Categorical variables belong to a class of variables with three or more possible response categories. An example of this type of variable can be the education achievement (Undergraduate degree, Master's degree, Doctoral degree) or college major (Music, History, Geography, Architecture).

Both dichotomous and categorical variables can be referred to as discrete variables. Discrete variables are variables that be counted and have clear and distinct categories.

Continuous variables refer to variables that can take on any numeric value with the possibility of being divided into smaller portions (including fractional and decimal values). Continuous variables are often measured on a scale. Examples of continuous variables include height, altitude, and weight.