its relative contribution at the end of the collaboration. The differing level of reward here refers to the predictive model (of varying performance) that is given back to the hospitals.

The first criterion stems directly from the profit-driven aim of hospitals - a better predictive model implies that a hospital can make more profits and thus clearly it prefers to gain more profits from collaboration than from other actions (one may find this similar to the idea of opportunity cost). On the other hand, the second criteria implies that hospitals holding high quality data, worried that smaller hospitals with relatively inferior data may become freeloader in the collaborative process, expects the reward given to be fair.

As a result, the central agency needs to find a sound way to measure the contribution of each hospital in the collaborative process and decide the value of model that should be given to each hospital after collaborating. In particular, it is important to investigate what defines an optimal outcome, if an optimal outcome is even possible and if not, what alternatives are possible. This motivates our paper.

Our contribution and research focus
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This paper taps heavily on concepts related to cooperative games 