Quantitative methods are research methods concerned with numbers and anything that is quantifyable. They are therefore to be distinguished from qualitative methods.
Counting and measuring are common forms of quantitative methods. The result of the research is a number, or a series of numbers. These are often presented in tables, graphs or other forms of statistics.
In most physical and biological sciences, the use of either quantitative or qualitative methods is uncontroversial, and each is used when appropriate. In the social sciences, particularly in sociology, social anthropology, and psychology, the use of one or other type of method has become a matter of controversy and even ideology, with particular schools of opinion within each discipline favouring one type of method and pouring scorn on the other. Advocates of quantitative methods have argued that only by using such methods can the social sciences become truly scientific; advocates of qualititative methods have argued that quantitative methods tend to obscure the reality of the social phenomena under study.
The modern tendency (and in reality the majority tendency throughout the history of social science) is to an eclectic approach. Quantitative methods are used in conjunction with qualitative methods. Using qualitative methods it is often possible to understand the meaning of the numbers produced by quantitative methods; using quantitative methods, it is possible to give precise and testable expression to qualitative ideas.
