A novel belief-based QFD-AHP model in interval type-2 fuzzy environment for lean after-sales service in automotive industry

Abstract

Purpose

The purpose of this paper is to propose a novel lean management tool to provide a comprehensive and flexible evaluation model while converting customer voices into technical characteristics in lean implementations.

Design/methodology/approach

For this purpose, the proposed model was constructed by belief space-evaluations, quality function deployment (QFD) and analytic hierarchy process (AHP) in interval type-2 fuzzy (IT2F) environment. This model involves three phases: determining the linguistic weights and belief-based relations with their IT2F-sets, processing information about IT2F-based belief-evaluations and ranking the technical characteristics using the defuzzified belief-based relative importance values.

Findings

The proposed model was applied to automotive after-sales service in Turkey to demonstrate its use in lean service-decisions. This model was compared with its classical and type-1 fuzzy versions. The ranking-results of the proposed model differed from those of the other versions. The reason is that the IT2F-environment offers a sensitive and flexible evaluation of the model’s linguistic scales.

Research limitations/implications

Calculations in the proposed model may be quite involved for practitioners. An Excel-dashboard was created to simplify the computational complexity.

Practical implications

Researchers/practitioners can apply this model to any lean manufacturing/service implementation.

Social implications

Company managers/employees/customers can recognize their perception-mechanisms via belief space-evaluations and experience how uncertainty in the perception-mechanism affects their decisions.

Originality/value

The proposed model provides a new lean tool due to the Bayesian model combined with QFD-AHP in IT2F-environment. This model eliminates the ambiguity in conceptual change-based lean decisions.

Citation

Baskir, M.B. (2023), "A novel belief-based QFD-AHP model in interval type-2 fuzzy environment for lean after-sales service in automotive industry", International Journal of Lean Six Sigma, Vol. 14 No. 3, pp. 653-678. https://doi.org/10.1108/IJLSS-03-2022-0055