What’s the difference between structured and unstructured interviews?

There are two distinct interview styles: structured and unstructured. Both have their place but serve different purposes. Depending on the data you want, one type may be more suitable than the other, or you may find a combination of the two works best.

As the name suggests, a structured interview has structure. It is a set of sequential, close-ended questions, where all interviewees are asked the same set of questions with the same response choices. The answer selection may be presented as multiple choice, a sliding scale, or yes/no.

It is sometimes called a standardized interview because it uses the same set of questions for each person and gathers information using the same set of variables. Answers are assigned a numerical value, making it simple to run data analysis.

Characteristics of a structured interview

Structured interviews make it easy for an interviewer since all the questions are the same with the same choices of responses. It allows for consistency and diminishes redundancy. Other characteristics include:

• Mainly quantitative data is gathered

• Easy to compile and replicate

• Sequential, asking the same questions in the same order each time

• Close-ended questions, such as multiple choice, point scale, sliding scale, or true/false

• Standardized, unbiased data

Advantages of a structured interview

Structured interviews are an easy way to gather data from standardized questions. Advantages include:

• Data collection and comparison are easy since all responses are quantitative. This allows you to compare all answers from the same set of possible responses throughout multiple interviews.

• Minimized the risk of leaving out important questions as the questionnaire is structured and uniform.

• Less opportunity for bias or favoritism.

• The interviewer can focus on the data instead of the interviewee or their personality.

• Less time is needed than for unstructured interviews, since the answers are close-ended and responses are readily available from a list of options, helping most respondents give a quick answer.

Disadvantages of a structured interview

Structured interviews have downsides too, including:

• More preparation time is needed. To make sure your questions are comprehensive and nothing is left out from the interview that will be used for all respondents, additional time may be needed to be sure that it is inclusive and that the results will yield the data that you need.

• Rating answers or simply answering with yes or no limits the respondent, who doesn’t have the opportunity to answer in depth. If more information is needed after the initial response, you may need to arrange an additional interview.

• Can be seen as impersonal.

• Respondents may feel their opinions are not valued.

Example of a structured interview

Structured interviews can be conducted over the phone, via a video call, or face to face.

You can use structured interviews to gather information on job applicants, product reviews, or during a marketing campaign. The applications for structured interviews are endless, but the most important thing to remember is that it is used to gather standardized, structured data.

Structured interview questions for a job applicant might be:

• What do people admire about you most?

• Your honesty

• The fact you’re hard-working

• Your loyalty

• Your personality

A question in a structured interview for a marketing campaign could be:

• How often do you purchase nutritional supplements?

• Weekly

• Monthly

• Annually

• Never

While structured interviews rely on standardized questions, unstructured interviews are quite the opposite. The interviewer may rely on spontaneity and ask questions about the topic being researched. It is more conversational, less formal, and usually more relaxed.

Questions are unprepared, but the interviewer must know the subject to present relevant questions. Interviewees are often less prepared for unstructured interviews since answers require thought and often opinion.

Unstructured interviews ask open-ended questions and feel more friendly than structured interviews.

Characteristics of an unstructured interview

Unstructured interviews rely on questions asked at the discretion of the interviewer. They are not standardized so can be very different across respondents. Other characteristics include:

• Informal approach

• Flexibility, because the interviewer can adapt and change the follow-up questions, depending on the interviewee’s responses

• Answers to unstructured interview questions are usually open-ended and based on personal preference or opinion

• Questions asked in an unstructured interview require spontaneity and thoughtful responses

• Descriptive in nature and a method of qualitative observation

Disadvantages of unstructured interviews

While unstructured interviews allow more flexibility than a more structured approach, there are some disadvantages to this approach. These include:

• Issues can arise when questions are not prepared in advance. You may forget to ask a question, get distracted, or let your bias stand in the way of gathering your data.

• Some interview respondents are not comfortable with open-ended questions and may struggle with accuracy or ease of response.

• Though time is saved during preparation, the interview itself can be more time-consuming.

• The questions are not standardized and the order they are asked may be out of sequence which can lead to confusion.

• They can generate large amounts of data that is not standard, making it hard to analyze the information gathered and use it effectively.

Example of an unstructured interview

Like structured interviews, unstructured interviews can be conducted over the phone, via a video call, or face to face. They can be used to gather the same general information about prospective employees, for marketing research, or other applications.

Unstructured interviews, however, are more relaxed and the questions allow the respondent to "fill in the blanks." Most unstructured interviews contain open-ended questions, allowing the respondent to voice an opinion, elaborate on an answer, or go into more detail. It is a friendlier, more personable approach.

An unstructured interview question for a job applicant might be:

• Tell me about the time you made a mistake at work but found a way to fix the problem.

A question in an unstructured interview for a marketing campaign could be:

• What do you like best about XYZ brand of nutritional supplements?

There are many differences between structured and unstructured interviews, including the tools used, the way data is compiled, and the kind of data collected. Some of the major differences are:

• Collecting data during the interview process usually differs. Both styles can be done in person or over the phone, but answers in a structured interview can be gathered via questionnaires and surveys, whereas an unstructured interview may rely on recorders, video equipment, or the interviewer's notes to record responses.

• In a structured interview, the data is mainly quantitative and objective. In an unstructured interview, the information is qualitative and more subjective.

• The amount of data samples, or respondents, involved can vary greatly between structured and unstructured interviews. Structured interviews can examine a large amount of data samples, while unstructured interviews usually involved a limited quantity.

• Structured interviews offer the same questions and the same blueprint for responses for all interviewees. Unstructured interviews allow respondents to go into detail.

• It is easier to compare data collected during a structured interview because it uses standardized questions and responses. Data from unstructured interviews is more time-consuming to analyze.

Although the processes are different, there are some similarities between the two kinds of interviews.

• They share the same goal of collecting relevant data.

• Both use respondents to gather the information needed.

• Both use the information to make comparisons, with the intent of minimizing bias.

Which interview style you use depends on the data you want to collect, how you will analyze it, and if you intend on doing additional research. If quantitative data collection is your goal, then structured interviews may be right for you. If you want more detail, to follow up on prior research, or if you are looking for qualitative data, unstructured interviews may be the best format.

How the research interview is conducted is also key. If you want to do the interview quickly with the use of standardized questions on a questionnaire, choose structured interviews. Unstructured interviews, however, allow you to be flexible, delve deeper into the interview, and spend time with the respondents.

In many cases, a blend of structured and unstructured approaches may be best. Some structured interviews may contain open-ended and close-ended questions, allowing some standardization along with the opportunity to elaborate on some of the structured answers.

Unstructured interviews are used to gather qualitative data in a flexible, less formal setting.

Unstructured interviews are best for getting detailed, qualitative data. They allow the respondent to give detailed, more spontaneous responses.

Unstructured interviews tend to be used by researchers who are familiar with the subject and want to gather in-depth information about it.