When constructs are defined in measurable terms, they are called variables. Variables are measurable characteristic that assumes different values within a class of objects or events. Variables must vary. A construct that does not vary within a class of objects or events is called a constant. This lesson introduces you to the various types of variables in social science research. There are three main types of variables: Independent (IV) and dependent variables (DV) where the independent influences the dependent variable; we have confounding variables that confuses the primary relationship between IV and DV and moderating variables that mediates the relationship between IV and DV. Confounding variables are of two types: Intervening and Extraneous variables. This lesson will take you through these variables giving examples and revision questions to ease our understanding.