Methods and systems for determining drug trend and drug inflation are described. In one embodiment, an index sample may be selected including an identification of a plurality of drugs. A weighting factor associated with each of the plurality of drugs in the index sample may be calculated. A first weighted price of for the plurality of drugs may be calculated for a first time period. A second weighted price for the plurality of drugs may be calculated for a second time period. A price index may be calculated for the second time period based on the first weighted price and the second weighted price. Other methods and systems are described.