Software Quality - Traditional vs. Agile: an Empirical Investigation
  It is well known that the software process impacts the quality of the resulting product. There are also anecdotal claims that agile processes result in higher level of quality than traditional methodologies. However, still solid evidence of this is missing. This work reports in an empirical analysis of the correlation between software process and software quality with specific reference to agile and traditional processes. More than 100 software developers and engineers from 21 countries have been surveyed with an online questionnaire. We have used the percentage of satisfied customers estimated by the software developers and engineers as the main dependent variable. The results evidence some interesting patterns: architectural styles may not have a significant influence on quality, agile methodologies might result in happier customers, larger companies and shorter projects seems to produce better products. 
Mohamad Kassab, JooYoung Lee, Manuel Mazzara, Giancarlo Succi, Rasul   Tumyrkin
cs.SE