Information Management in Improvement Projects: Qualitative and Linguistic Approaches to Value Stream Design

Abstract

A wide-spread approach to foster production and logistics related improvements on a system level is value stream mapping (VSM). It is often used as a starting point for implementing lean manufacturing in producing companies. VSM as a modeling approach contains two major phases – one is the analysis, another one the design phase. During these there is always the question of getting accurate information out of the production system to enable a constructive improvement. It can be distinguished between direct data acquisitions (observation, questioning, interviews) and indirect data acquisition (using IT systems) where both quantitative and qualitative data arises. Standard value stream design (VSD) offers no option to combine these data types, instead mostly deterministic values are used for assessing future states; this can lead to an illusion of accuracy. Thus in this paper it is shown how to combine different data types with an appropriate modeling using fuzzy variables in the course of VSD. The whole procedure is applied during a laboratory study to provide internal validity.