An empirical study on the usefulness of Conallen's stereotypes in Web application comprehension

Author(s): Filippo Ricca, Massimiliano Di Penta, Marco Torchiano, Paolo Tonella, and Mariano Ceccato
Venue: Proceedings of the Eighth IEEE International Symposium on Web Site Evolution (WSE'06)
Date: 2006


This paper was a study to determine the effects of Conallen's UML stereotypes on comprehension
of web-based applications. Conallen's stereotypes are a set of UML stereotypes designed with
web applications in mind. They add information on such things as navigation structure,
page generation, and form submission that UML diagrams do not normally contain explicitly. The
study was done on a class of software engineering students at the University of Trento, Italy.
The UML diagrams in the experiment were derived from 2 pre-existing web applications: Claros
and WfMS.

The experiment was done in two phases with 4 groups. Each phase was 2 hours long and it
is implied that they took place on separate days. The students were trained in Conallen's
notation prior to the experiment. In each phase, the students were given source code from
the application they were examining, UML diagrams derived from that code, and a questionnaire
of 12 questions. In the first phase, two groups got the code from Claros and two groups got the
code from WfMS. Of the groups with the same application, one's UML diagrams had Conallen's
stereotypes and the other's did not. In the second phase, each group switched applications
and UML type, so if they had been looking at Claros, they looked at WfMS (or vice-versa) and
if their UML diagrams had had stereotypes then now it didn't (or vice-versa). After each
lab, the students were given an additional questionnaire regarding the task, the system
complexity, whether they had had enough time to finish the lab, etc.

The various questionnaires were used to compile the results from the experiment. In all cases,
it was found that the students did better with Conallen's stereotypes than without. They answered
more questions correctly with the stereotypes and they spent between 60\% and 80\% more
time reading the diagrams (as opposed to the source code) when they had the stereotypes. This
implies that the students were able to gain much more of the relevant information from
the UML diagrams with Conallen's stereotypes than they were with the normal UML diagrams.

All in all, the experiment found that using Conallen's stereotypes in UML diagrams greatly
helps the comprehension of web applications.