Table of Contents
Advances in Software Engineering
Volume 2010, Article ID 685950, 17 pages
Research Article

The Economics of Community Open Source Software Projects: An Empirical Analysis of Maintenance Effort

Dipartimento di Elettronica ed Informazione, Politecnico di Milano, via Ponzio 34/5, 20133 Milano, Italy

Received 20 November 2009; Accepted 12 July 2010

Academic Editor: Giulio Concas

Copyright © 2010 Eugenio Capra et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Previous contributions in the empirical software engineering literature have consistently observed a quality degradation effect of proprietary code as a consequence of maintenance. This degradation effect, referred to as entropy effect, has been recognized to be responsible for significant increases in maintenance effort. In the Open Source context, the quality of code is a fundamental design principle. As a consequence, the maintenance effort of Open Source applications may not show a similar increasing trend over time. The goal of this paper is to empirically verify the entropy effect for a sample of 4,289 community Open Source application versions. Analyses are based on the comparison with an estimate of effort obtained with a traditional effort estimation model. Findings indicate that community Open Source applications show a slower growth of maintenance effort over time, and, therefore, are less subject to the entropy effect.