To survive in today’s competitive market environment, most of companies are increasingly focusing
on utilizing services to satisfy customers’ needs and offer differentiated products [1]. The value of
services depends on service reliability that is identified by satisfaction derived from the relationship
between customer needs and service providers. The reliability corresponds directly to the service
outcome and is mentioned as the most important dimension of assessing service quality [2]. The
service reliability can be measured by its processes’ reliabilities, since a service consists of many
processes. The service reliability is described as two delivery levels according to the promised
performance dependably and accurately [3, 4]. And, the reliability of a service process can be defined
as the capability of satisfying the specified performance requirements in a given period of time.
Products and systems usually have continuous distribution functions in terms of reliability and failure.
While service processes have discrete distribution functions and are independent from time. Therefore,
failure types or the numbers of failures can be considered as more important events than their
occurrence time or period [5]. Due to the characteristics of the services that are different from products,
methods or methodologies for analyzing the reliability of product are hard to apply in service reliability
analysis [5].
The objective of this paper is to propose an approach for assessing service risk and service
reliability using the service-oriented risk priority number based on fuzzy failure mode effects analysis
(FMEA) and grey relational analysis. The service reliability can be considered as mode and effects that
can be occurred at each step of the service process. Because the failure modes of services are distinct
from the failure modes of tangible systems, we need to develop a novel notion of a failure in a service
delivery process. We use an event-based process model to facilitate service design and represent the
relationships between functions and failures in a service. We define the failure mode of service as
interaction ways that can be failed in a service delivery process. The basic unit of a service is a
transaction which is a specific single instance of delivery of the service. In this paper, the fuzzy set
theory is used to define the frequency of failures in service processes and characterize service