On the Use of Emoticons in Open Source Software Development

TL;DR

This study analyzes how software developers use emoticons in issue trackers to understand sentiment expression and differences across regions and time, suggesting emoticons can complement sentiment analysis.

Contribution

It provides a large-scale empirical analysis of emoticon usage in open source development, highlighting regional and temporal differences and their potential for sentiment detection.

Findings

Mozilla developers use more emoticons than Apache developers.

Western developers use more emoticons than eastern developers.

Emoticon usage increases during weekends, especially for sad and surprised emoticons.

Abstract

Background: Using sentiment analysis to study software developers' behavior comes with challenges such as the presence of a large amount of technical discussion unlikely to express any positive or negative sentiment. However, emoticons provide information about developer sentiments that can easily be extracted from software repositories. Aim: We investigate how software developers use emoticons differently in issue trackers in order to better understand the differences between developers and determine to which extent emoticons can be used as in place of sentiment analysis. Method: We extract emoticons from 1.3M comments from Apache's issue tracker and 4.5M from Mozilla's issue tracker using regular expressions built from a list of emoticons used by SentiStrength and Wikipedia. We check for statistical differences using Mann-Whitney U tests and determine the effect size with Cliff's delta. Results: Overall Mozilla developers rely more on emoticons than Apache developers. While the overall ratio of comments with emoticons is of 2% and 3.6% for Apache and Mozilla, some individual developers can have a ratio above 20%. Looking specifically at Mozilla developers, we find that western developers use significantly more emoticons (with large size effect) than eastern developers. While the majority of emoticons are used to express joy, we find that Mozilla developers use emoticons more frequently to express sadness and surprise than Apache developers. Finally, we find that developers use overall more emoticons during weekends than during weekdays, with the share of sad and surprised emoticons increasing during weekends. Conclusions: While emoticons are primarily used to express joy, the more occasional use of sad and surprised emoticons can potentially be utilized to detect frustration in place of sentiment analysis among developers using emoticons frequently enough.