What if i Had No Smells?

What would have happened if I did not have any code smell? This is an interesting question that no previous study, to the best of our knowledge, has tried to answer. In this paper, we present a method for implementing a what-if scenario analysis estimating the number of defective files in the absence of smells. Our industrial case study shows that 20% of the total defective files were likely avoidable by avoiding smells. Such estimation needs to be used with the due care though as it is based on a hypothetical history (i.e., zero number of smells and same process and product change characteristics). Specifically, the number of defective files could even increase for some types of smells. In addition, we note that in some circumstances, accepting code with smells might still be a good option for a company.