Semi-Structured Interview

The semi-structured interview is a qualitative data collection strategy in which the researcher asks informants a series of predetermined but open-ended questions. The researcher has more control over the topics of the interview than in unstructured interviews, but in contrast to structured interviews or questionnaires that use closed questions, there is no fixed range of responses to each question.

Researchers who use semi-structured interviewing develop a written interview guide in advance. The interview guide may be very specific, with carefully worded questions, or it may be a list of topics to be covered. The interviewer may follow the guide to the letter, asking the questions in the order they are given, or the researcher may move back and forth through the topic list based on the informant's responses. In either case, the topics of the interview guide are based on the research question and the tentative conceptual model of the phenomenon that underlies the research.

Semi-structured interviews use many kinds of open-ended questions. Some questions may ask for relatively concrete information such as, “What did the doctor tell you about your mother's diagnosis?” Or they may ask for more narrative information such as, “How did you come to be the person who is taking care of your mother?” In addition to questions directly related to the concepts under investigation, semi-structured interviews also use a variety of probes that elicit further information or build rapport through the researcher's use of active listening skills. For example, the question, “What did the doctor tell you about your mother's illness?” might be followed up by a paraphrase such as, “So the doctor never used the word dementia?” or by a reflection such as, “It sounds like you were pretty upset.” Similarly, the question, “How did you come to be the person taking care of your mother?” could be followed up by a neutral probe such as, “Can you tell me more about what that was like?” Or if the response was lengthy, by a brief summary statement.

Semi-structured interviews are especially useful in research questions where the concepts and relationships among them are relatively well understood, such as in typological analysis; in contrast, unstructured interviews are more useful when the identification of important concepts is one of the research aims, such as in phenomenology. Because of the degree of structure in this interview format, the resulting text is a collaboration of investigator and informant. In order to ensure interpretive validity, the interviewer must avoid leading questions such as, “What was the main benefit of your mother's stay in the respite unit?” A better question would be, “How would you evaluate your mother's stay in the respite unit?” The latter question does not lead the informant into providing only one kind of evaluation. For both unstructured and semi-structured interviews, the development of rich, relevant data rests on the interviewer's ability to understand, interpret, and respond to the verbal and nonverbal information provided by the informant.