Subjectivity in Failure Mode Effects Analysis (FMEA) Severity Classification within a Reliability Centered Maintenance (RCM) Context

<p>This research paper investigated subjectivity in the severity rating of failure modes within a risk analysis process. Although several risk analysis processes can be utilized, the study considered the application of Failure Modes Effects Analysis (FMEA) or Failure Modes Effects and Criticality Analysis (FMECA) due to its common use within the Aerospace Industry. The study investigated both differences in severity selection given varying amounts of experience as well as any association between severity selection and the provided input information. The main goal of the research was to investigate the impact of data quality on severity selection and to identify factors that impact the severity score, and thus greatly influence the overall risk reduction strategies both in new acquisition and fielded systems. Participants consisted of both experienced and inexperienced FMEA/FMECA users. Participants were tasked to select a severity rating for nine failure modes (across three trials) assuming a typical severity scale. Different input data sets were provided in each trial to ascertain if an association exits between severity class selection and the amount of information available during analysis. This study provided evidence that risk analysis participants are subjective during severity rating selection when utilizing FMEA/FMECA processes. Users who are provided with irrelevant failure and mishap data tend to select similar severity levels; however, when no information is provided to users, user selections will be dramatically more conservative. Participants appear to select similar severity ratings regardless of the relevancy of the provided data.</p>