Failure Modes and Effects Analysis (FMEA) is an error analysis, which may involve retrospective investigations (as in Root Cause Analysis) or prospective attempts to predict “error modes.” Different frameworks exist for predicting possible errors. One commonly used approach is failure mode and effect analysis (FMEA), in which the likelihood of a particular process failure is combined with an estimate of the relative impact of that error to produce a “criticality index.” By combining the probability of failure with the consequences of failure, this index allows for the prioritization of specific processes as quality improvement targets. For instance, an FMEA analysis of the medication dispensing process on a general hospital ward might break down all steps from receipt of orders in the central pharmacy to filling automated dispensing machines by pharmacy technicians. Each step in this process would be assigned a probability of failure and an impact score, so that all steps could be ranked according to the product of these two numbers. Steps ranked at the top (i.e., those with the highest “criticality indices”) would be prioritized for error proofing.