Is ripple effect intuitive? A pilot study

The computation of ripple effect is based on the effect that a change to a single variable will have on the rest of a program; it determines the scope of the change and provides a measure of the program's complexity. The original algorithm used to compute ripple effect has been reformulated mainly to provide clarity in the operations involved. The reformulation involved some approximation which was shown not to affect the measures produced. The reformulated, approximated algorithm has been implemented as the software tool: Ripple Effect and Stability Tool ( REST). This paper uses a software development project as a case study to look at the relationship between the approximated ripple effect and a programmer's intuitive idea of ripple effect. Four versions of a mutation testing software tool were written in C over a period of several months. After the completion of each version the programmer was asked to detail his predicted/intuitive ripple effect for each module of code. The predictions are compared with the approximated ripple effect measures for each module and some surprising conclusions drawn.