Survey [1]

A survey, in the statistical sense, is a data-collection effort that focuses on facts or opinions related to human populations. The word "survey" can refer specifically to the survey instrument or to the entire process by which the data are collected. Surveys of human populations and institutions are common in political polling and government, health, social science and marketing research.

A survey may be administered to a random sample of the population of interest, a "convenience" sample of that population (whomever is available), or to the entire population, in which case it is called a census. The survey may be self-administered (distributed to respondents through regular mail, electronic mail, or a web site), administered by an interviewer by telephone, or administered by an interviewer in person.

The questions for a survey are usually structured and standardised. The structure is intended to reduce bias in the statistics developed from the survey (see questionnaire design). For example, questions should be ordered in such a way that a question does not influence the response to subsequent questions.

The advantages of survey techniques include:

  • Surveys are an efficient way of collecting information from a large number of respondents. Very large samples are possible. Statistical techniques can be used to determine validity, reliability, and statistical significance.

  • Surveys are flexible in the sense that a wide range of information can be collected. They can be used to study attitudes, values, beliefs, and past behaviours.

  • Because they are standardised, they are relatively free from several types of errors.

  • They are relatively easy to administer.

  • There is an economy in data collection due to the focus provided by standardised questions. Only questions of interest to the researcher are asked, recorded, codified, and analysed. Time and money is not spent on tangential questions.
Disadvantages of survey techniques include:
  • They depend on respondents’ motivation, honesty, memory, and ability to respond. Subjects may not be aware of their reasons for any given action. They may have forgotten their reasons. They may not be motivated to give accurate answers; in fact, they may be motivated to give answers that present themselves in a favorable light.

  • Structured surveys, particularly those with closed-ended questions, may have low validity when researching affective variables.

  • Although the chosen respondents are often a random sample, errors due to non-response may exist. That is, people who choose to respond on the survey may be different from those who do not respond, thus biasing the estimates.

  • Survey question answer-choices could lead to vague data sets because sometimes they are relative only to a personal, abstract notion concerning "strength of choice." For instance, the choice "moderately agree" may mean different things to different respondents, and to anyone interpreting the data for correlation. Even yes-or-no answers are problematic because subjects might put "no" if the choice "only once" is not available.

1. Based on the definition at Wikipedia (accessed 28 December 2006) [disclaimer].