Public opinion is an expression of the general population's thoughts on a particular issue and is often used in politics. It's most often determined through public opinion polls, which are surveys commissioned by various groups in order to determine people's thoughts on particular matters. These polls are conducted by polling organizations, which are businesses that measure public opinion through strategic methods. The Gallup Poll uses questions that are objectively worded. It also uses representative samples, which are polling sections that have the same basic characteristics as the general population. A sampling error occurs when a sample isn't representative of the general population. Polling organizations use a margin of error to address this possibility. The margin is a statistical measurement of how accurately the results of the poll reflect the real views of the population.