Variation is part of every process. Some variation is random and inherent in every process. Random (or natural) variation cannot be eliminated, but it can be optimally managed. Understanding and distinguishing between natural and artificial variation is the key to improving flow. Many quality and cost problems in a process or product are due to variation. The process that produces 95 percent on-time delivery or good product is the same process that produces the other 5 percent late deliveries or bad product. Reducing variation in such cases improves the predictability of outcomes (and may actually exceed customer expectations) and helps reduce the frequency of poor results. Use of protocols, changes in the triage process, and scheduling of elective surgeries based on historical demand for beds can help hospitals decrease and smooth variation.

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