An evaluation of APT: an Animated Program Tracer for novice Prolog programmers

Abstract

This paper describes an approach to evaluating the usefulness of an Animated Program Tracer (APT) in communicating run-time information to novice Prolo programmers. The method used in the evaluation consists of a set of programs which have been specially designed to elicit how novices think Prolog programs are executed, and thus to reveal how accurate their model of program execution is. Two experiments are reported. The first determines the misconceptions that novices hold about the runtime actions of the Prolog interpreter, and produces six different categories of misconception. The second experiment investigates the ability of APT to communicate run-time information to novice Prolog programmers. A scoring technique was used to interpret subjects' answers, and shows that there was a significant improvement in the scores of the group who saw programs traced by APT when compared with a control group who saw no trace.