Interviewing is one of the most widely used data collection methods in qualitative research. In business, management analysts and market researchers use interviews to gain managers' perspectives and gauge consumer preferences. Styles of interviewing techniques include the formal structured approach and the more flexible semi-structured form. The nature of the research being conducted helps determine the most appropriate type of interviews to conduct.
Structured interviews require the use of a set of standardized questions that the researcher creates in advance. Often, there are few open-ended questions in the interview guide, according to the qualitative research guidelines project at the Robert Wood Johnson Foundation in New Jersey. In this way, structured interviews resemble questionnaires or surveys. Semi-structured interviews also use an interview guide with some questions developed in advance but also allow the interviewer to stray from the interview guide, asking follow-ups as the interviewer believes appropriate. For example, an interviewee's responses to a prepared question may raise issues that the interviewer wishes to explore further follow-up queries.
Structured interviews keep the order and phrasing of the questions consistent across interviews to ensure consistency in the data being collected, the Robert Wood Johnson Foundation reported. In contrast, semi-structured interviews may prescribe a combination of questions and more general topics to cover. Questions in semi-structured interviews are more open-ended to allow interviewers to follow issues that diverge from the guide. Because of the open-ended responses, interviewers will often tape-record semi-structured interviews.
Researchers use structured interviews when they have a well-developed understanding of the topic being studied. When sufficient research literature exists to provide sufficient knowledge to develop relevant questions, a structured interview is sufficient, the Robert Wood Johnson Foundation reported. When the literature is less developed and the researcher wants to develop a better understanding of the topic under consideration, semi-structured interviews provide a way to gain additional knowledge by allowing respondents to express their views in their own words.
The Robert Wood Johnson Foundation noted that structured interviews leave little room for variation in the responses. This means that structured interviews make it easier to code the data for analysis. Semi-structured interviews reveal more open-ended qualitative data that require more time to analyze because the interviewer must read through notes and listen to transcripts, noting and summarizing important points and patterns.