Title: Health Care Systems Theory and Complexity Theory have lately, even if quietly, come together

Health Care Systems Theory and Complexity Theory have lately, even if quietly, come together.

Complex systems are complex unities formed of diverse, independent parts subject to a common plan and or serving a common purpose, the parts interacting with one another (1). The multiple responses of some parts to the influences of others may lead to "Emergent Properties": A completely new behavior of the system, utterly different from its past behavior (1).

Complex systems can arise from simple rules, and no way exists to predict the development of Emergent Properties under given rules or from the characteristics of the constituent parts (2).

Complex Adaptive Systems {i.e. possessing emergent behavior} can fail over-time because of the induced changes in the system due to Emergence (1). However, certain systems never develop Emergence. These are simple systems exhibiting Uniformity, Repetitiveness or Nesting (3) - see Figure. Uniformity implies no change whatsoever in the evolution of a system within itself. Repetitiveness occurs with rules allowing a limited number of system states. Nesting results from a tree-like branching exercise with small elements growing larger or conversely, due to various mechanisms rarely including constraints (4). These simple systems lacking Emergent properties will go on "forever" without the threat of self-induced failure.

Three methodologies influence today.s Health-Care Systems: The use of Protocols, of Evidence Based Practice and of Diagnosis Related Groupings {DRGs}.

Protocols embody uniformity - in Diagnosis, in logical utilization of data and in Treatment. Adherence to a recipe is at their core.

Evidence Based Practice limits the spectrum of choices of the practitioner leading to repetition - in diagnosis and than treatment. This may link into protocols leading to Uniformity - but this is not mandated.

DRGs came about to help resolve the chaotic ongoing in the domains of cost and reimbursement of Health-Care Systems. A tree-like classification linking diagnosis and procedures to costs - organized, systematized and simplified reimbursement. The DRGs taxonomy parallels the ongoing branching exercise of nesting systems.

Thus, Health Care Systems have evolved on their own and within themselves three major mechanisms which Complexity Theory recognizes as underlying systems which are immune to Emergence and Adaptability - minimizing the threat of failure due to a self-induced behavioral change over time. The smoother running and stability for the longer term of Health Care Systems including such components may augment their by now inbuilt lesser propensity to partial market failure (5).

Samuel Penchas
Hadassah University Hospital
Mount Scopus
Jerusalem 91120
Israel

1. Trefil J. The Nature of Science. Houghton Mifflin Company 2003; 88.
2. Wolfram S. A New Kind of Science. Wolfram Media Inc. 2002; 28, 240.
3. Idem. 351-361.
4. Idem. 360-361.
5. Penchas S. Complexity in Health Care. Complexus 2003; 1:149-156

Modeling of systems by printing the output of computer programs acting out given rules step-by-step. Each horizontal line of squares down the page is one step forward in time ("Cellular Automata").

At the top-Uniformity, in the middle-Repetitiveness and at the bottom-Nesting.

From {by permission}: Wolfram S. A New Kind of Science. Wolfram Media Inc. 2002; 25, 738.

Permission by Wolfram Media Inc. for figure was granted.