Suggestions for Use
Because structured interviews can provide a wealth of information about a student's understanding, interviews would seem to be strong candidates for use in formal ("summative") evaluation. However, the use of such interviews for individual evaluation is somewhat problematic. Using structured interviews in formal evaluation requires extended sessions with each student, a luxury that few faculty can afford except in relatively small classes. Instead, careful sampling and interviewing of a select but diverse group of students may permit you to develop an overall portrait of the various understandings that students in your class hold. This kind of "formative assessment" can provide detailed feedback that is very helpful in improving your teaching.
Structured interviews are very powerful tools for gaining insight into students' thinking. They are especially useful in diagnosing "learning errors", "misconceptions", and limitations in reasoning and critical thinking. With some training and practice, teaching assistants may be encouraged to use interviewing strategies in small groups and laboratory sections of large classes. Students themselves often find that knowledge of interviewing is useful in collaborative learning environments.
Step-by-Step Instructions
Several types of interview strategies have been developed for use in SMET disciplines (Southerland, Smith & Cummins, 2000). However, the "Interview about Instances and Events" (White & Gunstone, 1992) is possibly the most widely used format for probing understanding about single concepts. In this interview, the student is presented with a set of 10-20 line-drawings, photographs or diagrams that depict examples and counterexamples of natural objects (e.g., a mammal; a volcano; a planetary system; a molecule) or events (eg. a burning candle; a moving automobile; a girl throwing a baseball).
Revealing one drawing at a time, the student is asked to indicate whether it depicts an example of the concept in question, and to provide a rationale or justification. For example, consider a baseball in flight: Is there a "force" on the ball? What makes you say that? Tell me more about that. Or consider a burning candle: Is this "sublimation"? Why do you think that? Can you say some more about that? After each question, the instructor gently probes further into the reasoning the student uses and encourages him/her to elaborate on the responses to provide as complete a picture as possible of the student's understanding. A few general suggestions for conducting successful interviews:
- The interview should begin with a focus question that requires application of the concept to be investigated, without forcing the student into an explicit definition. A more traditional assessment might ask the student to choose the correct definition of the concept from among four choices or to write down a definition of the concept. The more indirect approach of a structured interview is usually more productive because it allows the student to evince her understanding rather than relying on memorized, rote definitions. This also enables the instructor to gain an idea of how the student applies the implicit concept.
- Do not force the student into a specific response to each graphic. If the student needs to "waffle" in her answer, she should be allowed to do so. If the student does not have an understanding of the concept that allows her to make a decision about a specific instance, do not force her to choose. This lack of understanding is an important piece of her "conceptual framework".
- Specific definitions of the concept, if needed, should be sought only after understanding the student's response to the focusing questions. Again, this prevents students from early closure on a rote definition. Thus, in our example, it would be inappropriate to ask, "Well, what is a force (or sublimation)?"
- It is important for the interviewer to wait at least 3 to 5 seconds after each prompt before trying to interpret the question or ask another. Classroom research has shown that when this "wait time" is observed, both the length of the student responses and the cognitive level of the responses increases (Rowe, 1974).
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