Quantitative research develops and employs mathematical models and hypotheses pertaining to phenomena. It is used social sciences such as psychology, sociology, economics and marketing, among many other disciplines. Quantitative research focuses on developing measurable outcomes using statistics.
Scientific methods used can include: generating theories, models and hypotheses, developing methods and instruments for measurement, experimental control and manipulating variables, collecting empirical data and analyzing the data. Typically a big sample of data is used, which requires validation and verification before the analysis can take place. The main research method is the randomised controlled trial, in which participants are assigned by chance to separate groups that compare different conditions.
Quantitative researchers study causal relationships by manipulating factors thought to influence the topic of interest while controlling other variables relevant to the experiment. Opinion surveys are another popular research method, widely used in the media. Respondents are asked a set of structured questions and their responses are categorized. An example might be the proportion of respondents in favour of a commonly reported point of view.