Research has shown that high school and university students have misconceptions about direct current resistive electric circuits. At present, there are no standard diagnostic examinations in electric circuits. Such an instrument would be useful in determining what conceptual problems students have before or after instruction. The information provided by the exam can be used by classroom instructors to evaluate their instructional methods and the conceptual problems of their students

Two versions of a diagnostic instrument known as Determining and Interpreting Resistive Electric circuits Concepts Tests (DIRECT) were developed, each consisting of 29 questions. DIRECT was administered to groups of students in the United States, Canada and Germany that had completed their study of electrostatics and direct current electric circuits.

Individual interviews were conducted after the administration of version 1.0 to determine how students interpreted the questions and to uncover the reasoning behind their selections. The analyses indicate that students, especially females, tend to hold multiple misconceptions, even after instruction. The idea that the battery is a constant source of current was used most often in answering the questions. Although students tend to use different misconceptions for each question presented, they do use misconceptions associated with the global objective of the question. Students' definitions of terms used on the exam and their misconceptions were examined. Students tended to confuse terms, especially current. They assigned the properties of current to voltage and/or resistance.

One of the major findings was that students were able to translate easily from a "realistic" representation of a circuit to the corresponding schematic diagram. Results indicated that students do not have a clear understanding of the underlying mechanisms of electric circuit phenomena. Students had difficulty handling simultaneous changes of variable.