Market research involves systematically gathering, recording, and analyzing data about problems related to marketing goods and services. There are two main sources of information for organizations: primary and secondary. Primary research involves directly collecting new data through methods like surveys, interviews, and observations. Secondary research uses already existing data from external sources like government publications, competitors, and market research organizations. When conducting primary research, organizations must make decisions around who to survey, how many people, and how to select the sample. Common sampling methods include random, stratified random, and quota sampling. Both primary and secondary research provide benefits to organizations like aiding decisions and reducing risk, but also have limitations such as potential bias and changes in opinions over time.