The Effect of Lexicon Bad Smells on Concept Location in Source Code

Experienced programmers choose identifier names carefully, in the attempt to convey information about the role and behavior of the labeled code entity in a concise and expressive way. In fact, during program understanding the names given to code entities represent one of the major sources of information used by developers. We conjecture that lexicon bad smells, such as, extreme contractions, inconsistent term use, odd grammatical structure, etc., can hinder the execution of maintenance tasks which rely on program understanding. We propose an approach to determine the extent of this impact and instantiate it on the task of concept location. In particular, we conducted a study on two open source software systems where we investigated how lexicon bad smells affect Information Retrieval-based concept location. In this study, the classes changed in response to past modification requests are located before and after lexicon bad smells are identified and removed from the source code. The results indicate that lexicon bad smells impact concept location when using IR-based techniques.