A laboratory experiment was conducted to assess the basic theory and extensions to the theory for recursive tasks across programming languages. The experiment used 34 LISP and 48 PASCAL computer science students in two repeated measures designs. Findings of the study are reported and analyzed. The results strongly suggest that investigation of programming constructs should take place in the context of specific programming languages. Since a number of languages provide similar kinds of programming constructs, it is difficult for programmers to choose those implementations that best suit their needs. One way of encouraging the use of desirable constructs would be to develop languages adapted to certain types of tasks. Such an approach would inherently lead to cognitive fit and the attendant performance benefits would be realized.>

The results of an exploratory study that investigated expert and novice debugging processes with the aim of contributing to a general theory of programming expertise are reported. The research had two major objectives. First, it sought to control for the variability in individual problem solving by incorporating certain aspects of subjects' debugging processes into the debugging model. The criterion of expertise was the subjects' ability to chunk the program they were required to debug. This method proved effective at explaining much of the variability in debugging time and the number of errors subjects made and, hence, afforded information on the differences in the debugging processes of experts and novices. Second, the study assessed the nature of the differences in expert and novice debugging processes by analyzing the data at two levels, representing different degrees of dependence on the current problem solving environment. The literature suggests that novices rely on formal models in problem solving while experts react principally to the task environment as revealed during problem solving. The method used was verbal protocol analysis. Data were collected from sixteen programmers employed by the same organization. An a priori task analysis was used as the basis for a content analysis of the protocol data. The research provided some support for the notion that experts are situation-dependent problem solvers, while novices are situation-independent problem solvers.

In spite of the widespread acceptance by academics and practitioners of structured programming precepts, relatively few formal empirical studies have been conducted to obtain evidence that either supports or refutes the theory. This paper reviews the empirical studies that have been undertaken and critiques them from the viewpoints of the soundness of their methodology and their ability to contribute to scientific understanding. In general, the evidence supporting programming precepts is weak. A framework for an ongoing research program is outlined.