6.2 Failure Criticality Analysis for the Hypermarket Example and Discussions
To perform the FMEA, the service system of a hypermarket store is decomposed into
four sub-systems: service facility, pre-service, in-service, and post-service. Each sub-system
involves several sub-processes or activities. In the service failure analysis, the potential failure
modes for each sub-process/activity are developed and listed according to the service
blueprint.
To accomplish the service failure analysis systematically, the service system of a
hypermarket store is decomposed into four sub-systems: service facility, prior-service,
in-service, and post-service. Each sub-system involves several sub-processes or activities.
Among these, service facility involves sales floor facility, sales floor security, and sales floor
surroundings. Prior-service involves incoming goods/merchandise activity as well as
warehousing and inventory activity. In-service involves customer choose/purchase flow and
cashier flow. Post-service involves post-sale activity and warranty. The potential failure
modes for each sub-process/activity are then explored and listed according to the service
blueprint of the hypermarket store. In this regard, twenty three potential failure modes, in total,
are structurally listed for further analysis.
To compute the risk priority number (RPN) that differentiate the effect of each potential
failure modes, the required data of severity rating, occurrence rating, and detection rating are
collected by a questionnaire survey. This survey was assisted by a chain hypermarket store,
which has four branch stores in Taiwan (We will call it T-store in the rest of the paper). By
prior contact with the T-store and having their approvals, one hundred questionnaires were
sent to the employees of the T-store. Among those, 6 are executive managers, 16 are
middle/floor managers, and 78 are first-line servers. The respondents were asked to rate the
degree of severity, the probability of occurrence, and the degree of detection ability of each
failure modes. In the questionnaire, a five-scaled rating from 1 to 5 is used for each failure
modes. That is, for the severity rating, 1 means the least severe it is if the corresponding
failure mode occurs and 5 means the most severe; for the occurrence rating, 1 means the least
likely it is for the corresponding failure mode to occur and 5 means the most likely; for the
detection rating, 1 means that the store has the highest degree of control ability to prevent the
corresponding failure mode from occurring and 5 means the lowest degree of control ability