The basic idea behind survey methodology is to measure variables by asking people questions and then to examine relationships among the variables. In most instances, surveys attempt to capture attitude or patterns of past behavior. About the only options are whether to ask people questions once or over time. The most commonly seen survey uses the cross-sectional design , which asks questions of people at one point in time. These kind of surveys are highly fallible because the researcher may or may not be able to analyze the direction of causal relationships.
Surveys vary widely in sample size and sampling design.
Large-scale probability surveys are the ideal, and the target population is a whole country, like the United States. A questionnaire almost always is self-administered, allowing respondents to fill them out themselves. All the researcher has to do is arrange delivery and collection. Although surveys can be a cost-effective type of research, survey research design suffers from inherent weaknesses. The greatest weakness is probably due to the fact that all surveys are basically exploratory .