Table 2.

Application of Network Concepts to Public Health Problems in Critical Care

Public Health Problem	Network Concept	Testable Hypothesis
Will regionalization of adult critical care services improve outcomes?	Centralization: networks quantitatively differ in the extent to which relationships are concentrated in a few nodes.	Regions of the country with more centralized referral networks have improved risk-adjusted population outcomes from selected critical illnesses.
Which patients should be transferred?	The benefits of network position may be a function of characteristics of the individual who occupies that position.	The benefits of a transfer will result from an interaction between characteristics of the patient, the sending hospital and the receiving hospital.
Does health insurance limit a patient's treatment options for critical illness?	Network regression allows statistical comparison of different networks.	Transfer networks for different insurers will be statistically indistinguishable.
Do for-profit hospitals “cream skim” patients?	Individual hospital characteristics can be statistically correlated with quantitative measures of network position.	Hospital for-profit status will not be associated with position in the network.