Figure 6
From: The interhospital transfer network for very low birth weight infants in the United States
The regionalization index and the proportion not transfered are positively associated. We performed an ordinary least-squares regression between the regionalization index and the proportion of all infants born in a given community who were never transferred. In this regression, we controlled for the total number of hospitals in each community and the fraction of each community that were VON member facilities (we only had data on the proportion not transfered for VON member hospitals). The results were robust to removal of the point in the lower-left corner where there were all infants were transfered and the regionalization index was zero (regression results with “outlier” removed: adjusted \(R^{2} = 336\); \(p < 0.001\))