Surveys

Surveys are systematic methods for collecting information from a subset of individuals to describe characteristics of a larger population. They are used in research, policy, and business to measure opinions, behaviors, experiences, or attributes. A survey typically combines a sampling design with a data collection instrument, such as a questionnaire or a structured interview, and a plan for data processing and analysis. The goal is to produce estimates that generalize to the target population within a quantified margin of error.

Sampling aims to obtain a representative subset. Probability sampling methods, such as simple random or stratified sampling, provide known chances of selection and support generalization. Nonprobability samples may be faster or cheaper but can introduce bias. Sample size, response rate, and weighting influence precision and bias.

Question design and mode of administration affect responses. Questions should be clear, neutral, and not leading. Closed-ended items enable quantitative analysis; open-ended items capture qualitative detail. Surveys can be conducted online, by telephone, by mail, or in person, with mode effects and coverage issues to consider.

Data processing includes data cleaning, coding, and weighting to reflect the population. Analysis typically reports descriptive statistics and may involve inferential methods such as regression or hypothesis testing. Reliability and validity are considered through pretesting, pilot studies, and measurement redesign.

Ethical considerations include informed consent, confidentiality, and protection of respondents' data. Researchers may seek review by an ethics committee or institutional review board. Surveys have a long history in public opinion research and social science, with improvements in sampling, measurement, and online data collection driving broader use across sectors.