  Due to their pivotal role in software engineering, considerable effort is
spent on the quality assurance of software requirements specifications. As they
are mainly described in natural language, relatively few means of automated
quality assessment exist. However, we found that clone detection, a technique
widely applied to source code, is promising to assess one important quality
aspect in an automated way, namely redundancy that stems from copy&paste
operations. This paper describes a large-scale case study that applied clone
detection to 28 requirements specifications with a total of 8,667 pages. We
report on the amount of redundancy found in real-world specifications, discuss
its nature as well as its consequences and evaluate in how far existing code
clone detection approaches can be applied to assess the quality of requirements
specifications in practice.
