Cost implications of interrater agreement for software process assessments

Much empirical research has been done recently on evaluating and modeling interrater agreement in software process assessments. Interrater agreement is the extent to which assessors agree in their ratings of software process capabilities when presented with the same evidence and performing their ratings independently. This line of research was based on the premise that lack of interrater agreement can lead to erroneous decisions from process assessment scores. However, thus far we do not know the impact of interrater agreement on the cost of assessments. In this paper we report on a study that evaluates the relationship between interrater agreement and the cost of the consolidation activity in assessments. The study was conducted in the context of two assessments using the emerging international standard ISO/IEC 15504. Our results indicate that for organizational processes, the relationship is strong and in the expected direction. For project level processes no relationship was found. These results indicate that for assessments that include organizational processes in their scope, ensuring high interrater agreement could lead to a reduction in their costs.