FLAG - Classroom Assessment Techniques (CATs)

Interviews    (Screen 2 of 6)

Description
In its simplest form a structured interview is simply one person asking another person a series of questions about a carefully selected concept/topic or asking her to perform a task. Any materials to be used (props, problems, etc.), many of the questions to be asked, and some responses from the interviewer to expected statements or actions of the interviewee are carefully planned in advance. Importantly, however, the interviewer is free to ask additional questions that focus on issues arising during the course of the interview. It is this freedom to follow the interviewee, to ask for clarifications, and to focus on errors, misconceptions, and gaps in knowledge, that makes the interview so much more fruitful than more traditional methods of assessment.

During a structured interview, the instructor uses a set of questions, called "probes" (and sometimes selected photographs or other props) designed in advance of the interview to elicit a portrait of the learner's understanding about a specific concept/topic (e.g., evolution; molecular/kinetic theory; plate tectonics; binary stars; Newton's laws). The student may be asked to use her own words to explain a concept (e.g., "What is natural selection?") but is typically required to go beyond simple recognition of a concept to construct a detailed personal explanation. Typically the student is also asked to use that concept to solve a problem or other application task (e.g., "Explain why cave fish have no color"). Valuable information is often obtained not only from listening to what the interviewee says, but also from observing what she does, including facial expressions and other body language.


Assessment Purposes
Structured interviews may serve many functions, among them:

It is also important to note that the goal of the interview is to describe how a student understands a scientific concept or phenomenon, and not simply to provide a measurement of the degree to which this understanding approximates the scientific explanation. Thus, interviews are typically used to provide the instructor with insight about students' understandings in order to refine and target instruction ("formative assessment") rather than to evaluate the knowledge of individual students for purposes of assigning a grade ("summative assessment").

Structured interviews are used to describe individual student's understandings of a specific scientific concept or closely related groups of concepts. It is important to note, however, that the degree of understanding to be assessed will differ depending on the type of interview probe used. Can the student recognize the concept? Generate an example? Apply the concept? Use the concept to predict phenomena or solve problems? Different kinds of structured interviews measure different degrees of understanding.


Limitations
Structured interviews are used to describe individual student's understandings, and are best conducted individually with students; thus time is a major inhibiting factor in using structured interviews to inform teaching. To prevent this issue from being prohibitive, selective sampling of a broad range of students in a classroom may be employed to make the technique more practical, yet still provide a portrait of how different students in a class are engaging with course material.

A second limitation of structured interviews lies in the extreme content specificity of students' thinking. For instance, when dealing with biological knowledge, the type of organism included in an interview prompt has been shown to radically change the nature of a student's response. Thus, if an instructor would like to probe a student's reasoning pattern about a specific process (e.g., the change of coat color in response to environmental cues) the nature of the exemplar (eg. the organism) included in the probe must be taken into account (Tamir & Zohar, 1992). Similar specificity may be expected in virtually all scientific disciplines.

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