Sociology applies scientific methods to the study and understanding of human society. Social units ranging from the family to modern industrial society attract the interest of sociologists. Like all scientific research, sociological studies search for a cause-and-effect relationship between two phenomena. Sociologists classify social phenomena being studied as independent and dependent variables. Understanding social research requires knowledge of the difference between these classes of variables.
A dependent variable in sociology and other social sciences is the effect, the phenomenon affected or changed by other actions or phenomena. Examples of dependent variables in sociology include levels of crime or poverty in neighborhoods, racist attitudes or order within a civil society. Sociologists often study the ways in which numerous programs, activities and other phenomena impact these and other dependent variables. For example, sociologists interested in crime may ask how certain factors affect urban crime rates. In this example, urban crime rate is the dependent variable. Sociologists often represent the dependent variable mathematically by using the letter "Y."
Independent variables are those factors, activities and other phenomena that change or affect the value or level of a dependent variable. Sociologists often represent independent variables mathematically with the letter "X." A typical sociological research question may ask the manner and extent to which X influences dependent variable Y. A sociologist who studies criminal behavior may ask how lack of economic opportunity affects urban crime rates. For such a study, lack of economic opportunity represents the independent variable, while urban crime rate is the dependent.
Many independent and dependent variables in sociology and other social sciences do not lend themselves to easy measurement, meaning that researchers must carefully think about one or more measures to investigate the phenomena they wish to study. For example, they may need to design questionnaires to measure subject attitudes about race or use government-collected data on economic or criminal activity to measure levels of wealth or crime across social classes.
In addition to measurement issues, the lack of laboratory controls available to researchers in the natural sciences further complicate sociological research. Social research occurs in the real world of social interactions, meaning that sociologists cannot randomly assign subjects to experimental and control groups for research purposes. This makes it difficult to attribute changes in a dependent variable to the independent variable. This means sociologists must often conduct complex statistical analysis to control other factors besides the independent variables of interest that may affect the dependent variable.