Field Survey

Advantages and Disadvantages

Field surveys have several advantages over other modes of data collection. Lengthy, complex instruments are easier to administer in a face-to-face interaction in which the interviewer can clarify questions, [Page 280]present visual aids, probe responses, and assess respondent fatigue. In countries like the United States that do not maintain a national registry of residents, selecting neighborhood blocks and listing the housing units on selected blocks, as is often done for field surveys, provides more complete coverage of the household population than do studies based on telephone numbers or mailing addresses. Response rates are typically higher in face-to-face surveys.

On the other hand, field interview costs are very high relative to other modes of data collection, sometimes 5 to 10 times those for telephone surveys. Large field data collections involve significant time for planning and implementation and require hiring, training, and supervising a large, geographically dispersed field staff. In terms of data quality, the presence of an interviewer may cause respondents to adjust their answers to survey items in order to report socially appropriate or desirable responses.

Variations

Field surveys can be implemented in a number of ways and can be used to collect a wide range of data. It is common to record interviewer observations on characteristics of the neighborhood and housing unit. In surveys that ask for sensitive information such as drug use or sexual behavior, some questions may be self-administered; that is, respondents read and answer the questions on their own either during or after the interview. For example, the National Survey on Drug Use and Health, a large annual field survey of approximately 70,000 U.S. persons 12 years old and older, which is sponsored by the U.S. Substance Abuse and Mental Health Services Administration and conducted by RTI International, uses ACASI (audio computer-assisted self-interviewing) in which respondents listen to questions using earphones and enter their responses on a laptop computer.

Field survey protocols may include the administration of tests of physical performance (e.g. walking speed, grip strength) or cognitive ability (e.g. memory tasks, word recognition) or the recording of physical measurements (e.g. height, blood pressure). Biological specimens such as blood or saliva or environmental specimens such as soil or dust may be taken as part of the in-person visit, as is done, for example, in the National Health and Nutrition Examination Survey. In mixed-mode studies, sample members may first be asked to complete the survey using mail, Internet, or telephone modes. Only those sample members who do not respond via these modes are followed up with a more expensive field survey request. In panel studies that collect data from the same persons at multiple time points, like the Current Population Survey, field interviewing may be used in the initial interview to motivate sample members to participate and report accurately. Later rounds of interviews are then completed using less expensive telephone interviews.

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