Figure 1, top left, A, maps the 30 Connecticut hospitals engaging in a critical care transfer of a Medicare fee-for-service patient during 2005. Figure 1, top right, B, adds transfer information to the map, with arrowheads reflecting the direction of the transfer and line thickness proportional to the number of transfers. Because cardiovascular disease is a common indication for transfer, Figure 1, middle left, C, adds information about hospital capabilities: catheterization laboratory, cardiac surgery, or neither. In Figure 1, middle right, D, hospitals that receive more transfers are shown with larger markers, embedding network characteristics in the graphical representation. Figure 1, bottom left, E, a network visualization algorithm, demonstrates the transfer networks in Connecticut as having two distinct centers, one in New Haven, one in Hartford. Hartford has two major hospitals of nearly equal importance in this network. The other hospitals in the state are more peripheral, and many are connected to both core cities. This initial test provides little graphical support for hypothesis H2 (satellites of a single center).