Statistical analysis of downtime severity rates

As an aid in evaluating efforts to reduce process downtime rates and to facilitate resource allocation decisions, a model of the downtime severity rate and statistical methods for estimating and evaluating two or more downtime severity rates are presented. Time down or cost per downtime incident is assumed to follow a gamma distribution. An expression for a one-sided upper statistical tolerance limit on the downtime severity rate is derived. Examples of statistical analysis using data from a paper manufacturing facility are provided.