reduction and defect reductions in care. It all depends upon how much waste and inefficiency we as a profession are willing to tolerate—or how much systematic improvement and standardization we are willing to build into our work.


Eugene Litvak, Ph.D., Sandeep Green Vaswani, M.B.A., Michael C. Long, M.D., and Brad Prenney, M.S., M.P.A.

Institute for Healthcare Optimization

The healthcare delivery system falls short for all stakeholders: patients, providers, and payers. Indeed, despite record-breaking and fast growing costs, today’s healthcare system is still characterized by overcrowded ERs, stressed and overloaded clinicians, unnecessarily low quality of care, and extensive waste. And although many factors have been cited as drivers of this state of affairs, one key driver is often overlooked: unmanaged variability in patient flow.

Artificial Flow Variability

Variability, particularly in the flow of patients through the healthcare delivery process, impedes cost reduction and improvement of patient safety and quality of care (Aiken et al., 2002; Joint Commission Resources, 2009; Litvak, 2005, 2007; Litvak and Long, 2000; McManus et al., 2003). Some patient flow variability is natural, such as the flow of patients admitted to a hospital unit through the ER. However, it is the artificial variability where there is room for improvement. Artificial variability is the result of mismanagement. It is not driven by the timing of patients’ illnesses but by the mismanagement of scheduling and allocating limited hospital resources. Furthermore, it is simultaneously neither random nor predictable (Litvak and Long, 2000). The flow of elective admissions (such as elective surgical, catheterization lab, oncology admissions) to a hospital is just such an example of artificial variability. In fact, it is often comparable if not greater than the natural variability in ER admissions (see elective surgery example in Figure 9-3).

Effects of Artificial Variability in Patient Flow

While the most visible effects of artificial flow variability on hospital function are in ER overcrowding, boarding, and diversion, this unnecessary variation drives problems in quality, capacity, and cost.

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