Does the combined use of class and sequence diagrams improve the source code comprehension?: results from a controlled experiment

We present the results of a controlled experiment aimed to investigate whether the source code comprehension increases when participants are provided with UML class and sequence diagrams produced in the software design phase. The experiment has been conducted with Master students in Computer Science at the University of Salerno. The data analysis shows that the participants significantly better comprehend source code when it is added with class and sequence diagrams together.