Survey Instrument, Questionnaire, Statement

A questionnaire, survey instrument, and statement form are all variations of the same thing:

closed-ended

open-ended questions

The process of administration of the questionnaire may be:

self-administered, such as when the questionnaire is mailed to potential respondents, sent through electronic mail to potential respondents, or made available on a web site;
administered face-to-face by an interviewer or statement taker to one respondent or multiple respondents simultaneously; or
administered over the telephone by an inteviewer or statement taker.

If the list of questions is being administered through a random sample survey, then that list of questions is usually called a questionnaire or survey instrument. If the list of questions is being administered to a set of volunteer respondents, and is composed primarily of open-ended questions, then the list of questions is called a statement or statement form. This is often the case when statements about human rights abuses are collected by non-governmental organisations.

Designing a questionnaire is a complex process. Care must be taken to create questions of clear and simple meaning, laid out in such a way as not to confuse the respondent (in self-administered surveys) or the interviewer (in non-self-administered surveys). In addition:

From a technical point of view, a question must not induce a specific answer. Dishonest researchers or surveyors might draw false evidence from inductive questions to support their thesis. But even sincere researchers might inadvertently lead the respondents towards answers that do not reflect their actual situation or opinion.
From an ethical point of view, a question must avoid “undue stress through participation, loss of self-esteem, psychological injury or other side effects” (International Statistical Institute: Declaration on Professional Ethics §4.4, 1985).

A good questionnaire design process is essential for the creation of a high-quality questionnaire.