Probing

Probing involves the use of specific words or other interviewing techniques by an interviewer to clarify or to seek elaboration of a person's response to a survey question. When respondents provide incomplete or irrelevant answers to survey questions, it becomes necessary for interviewers to query respondents further in an effort to obtain a more complete or specifie answer to a given question. Although survey researchers may take great care in constructing questionnaires in terms of the wording of both questions and response options, some respondents may not provide a response in the format pre-specified by the researcher, especially when answering closed-ended questions. Likewise, respondents may offer vague or overly simplistic replies to open-ended questions, that is, questions with no predetermined response categories. Additionally, respondents may simply provide the response, “I don't know,” which the researcher may or may not want to accept as a valid response.

The following are examples of responses requiring probing:

To elicit an acceptable response to a given item, interviewers should use an appropriate neutral, unbiased, or “nondirective” probe. Interviewers should take care to elicit the information needed without suggesting or leading the respondent to a particular response. Researchers should include suggested wording for potential probes in their questionnaires, in an effort to equip interviewers to handle these situations. Although every situation is different, there are some basic techniques and general rules that most interviewers find successful when probing respondents for information.

• 1.
  Repeat the question. When respondents appear to have misunderstood or misinterpreted a survey question, repeating the question is the best probe. This technique is used with the expectation that after hearing the survey question a second time, the respondent will understand what information the question is intended to collect.
• 2.
  Silent probe. Interviewers may also use a silent probe, which is a pause or hesitation intended to indicate to a respondent that the interviewer may be waiting for additional information or clarification on a response. Oftentimes, interviewers will utilize this technique during later stages of an interview, once a respondent's habits or response patterns have become more obvious.
• 3.
  Neutral question or statement. When a respondent offers an inadequate response, interviewers use neutral questions or statements to encourage a respondent to elaborate on their initial response. Examples of good neutral probes are “What do you mean?” “How do you mean?” “Please tell me what you have in mind,” “Please tell me more about …” Note that these probes maintain neutrality and do not lead the respondent by asking things such as “Do you mean you don't support the bill?”
• 4.
  Clarification probe. When a response to an item is unclear, ambiguous, or contradictory, interviewers will use clarification probes. Examples of good clarification probes are “Can you give me an example?” or “Could you be more specific?” Whereas these probes are helpful, interviewers must be careful not to appear to challenge the respondent when clarifying a statement. Interviewers must know when to draw the line between probing a respondent for more or better information and making the respondent feel pressured to answer an item, which could lead to an outright refusal to continue participation in the rest of the survey.

Most interviewers will agree that “I don't know” is the response to survey items requiring probing that occurs most frequently. Because a “don't know” response is vague and can mean any number of things, interviewers are often challenged with the need to choose the correct probe. Interviewers are also challenged to not cross the line between probing and pressuring in this situation as well. Interviewers are trained to remind respondents that participating in a survey is not a test, and that there are no right and wrong answers. A good practice for interviewers is encouraging a given respondent who provides a “don't know” response to an item to give his or her “best estimate,” or “best guess.” Encouraging the respondent to answer [Page 626]an item and reminding them that their answers, no matter what they are, are the “right answers” to a given question will likely lead to better consideration of the question and a higher quality response.

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