Part of a larger line of inquiry on the socially constructed experience of the mediated classroom and student socialization in the university community, a study reports on the development of an instrument for tapping student experience in televised instruction classrooms. A theoretical framework underlies the instrument to illuminate reasons for student judgments about the positive and negative learning experiences in the class. Items are structured so that the reasons include expressions of personal responsibility for success or shortfalls as well as attributions of responsibility to external conditions. Findings based on using the instrument in a physics course (in which teaching assistants interact with students off campus before and after rebroadcasts of the videotaped lectures) show how the item format contributes to understanding why students make the evaluative judgments that they do and these are drawn upon to illuminate three issues relevant to instructionally appropriate evaluation: effectiveness/quality; commitment/stakeholders; and access/resources. (Contains 13 references and a note). (RS)