1. A computer-implemented method for scoring a population of examples subject to an additional constraint of a fixed aggregate resource expenditure, the method comprising: generating a master gain ratio list that identifies, for each example in the population of examples, an attribute combination having a largest gain ratio among all attribute combinations in the example, wherein the master gain ratio list is generated using an iterative process comprising: identifying a plurality of attribute combinations associated with the example, wherein for each attribute combination of the plurality of attribute combinations at least one attribute in the attribute combination indicates a resource expenditure for the attribute combination, using a predictive model to determine a predicted gain value for each attribute combination, determining a gain ratio for each attribute combination, wherein the gain ratio for an attribute combination is defined as the predicted gain value for the attribute combination divided by the resource expenditure for the attribute combination; identifying a particular attribute combination in the plurality of attribute combinations having the largest gain ratio, and adding the particular attribute combination and the largest gain ratio to the master gain ratio list; sorting, by the computer system, the master gain ratio list according to the gain ratio; and performing the resource expenditure associated with a first attribute combination on the sorted master gain ratio list.