14. A system, comprising: a data store storing a dataset associated with one or more types of performance measures; and one or more processors that interact with the data store and execute instructions that cause the one or more data processing apparatus to perform operations comprising: receiving one or more requests for a first type of performance measure; identifying, based on the one or more requests and from a dataset, a proper subset of data used to determine a value for the first type of performance measure; determining the value based on the proper subset of data; determining a first latency specifying an amount of time that was required to determine the value using the dataset; defining a pre-aggregated dataset that includes the proper subset of data from the dataset; calculating a benefit score for the pre-aggregated dataset based on a difference between the first latency and a second latency specifying an amount of time required to respond to the request using the pre-aggregated dataset; adjusting the benefit score as a rate of received queries for the first type of performance measure changes over time; determining, at a given time, that the adjusted benefit score meets a threshold value; and storing the pre-aggregated dataset in response to determining that the benefit score meets the threshold value.
14. A system, comprising: a data store storing a dataset associated with one or more types of performance measures; and one or more processors that interact with the data store and execute instructions that cause the one or more data processing apparatus to perform operations comprising: receiving one or more requests for a first type of performance measure; identifying, based on the one or more requests and from a dataset, a proper subset of data used to determine a value for the first type of performance measure; determining the value based on the proper subset of data; determining a first latency specifying an amount of time that was required to determine the value using the dataset; defining a pre-aggregated dataset that includes the proper subset of data from the dataset; calculating a benefit score for the pre-aggregated dataset based on a difference between the first latency and a second latency specifying an amount of time required to respond to the request using the pre-aggregated dataset; adjusting the benefit score as a rate of received queries for the first type of performance measure changes over time; determining, at a given time, that the adjusted benefit score meets a threshold value; and storing the pre-aggregated dataset in response to determining that the benefit score meets the threshold value. 17. The system of claim 14 , wherein the instructions cause the one or more data processing apparatus to perform operations comprising: receiving, after storing the pre-aggregated dataset, a different request for a different type of performance measure; determining that using the pre-aggregated dataset to determine a value for the different type of performance measure lowers a latency for responding to the different request relative to a latency for responding to the different request using the dataset; determining, in response to the determination that using the pre-aggregated dataset lowers the latency relative to using the dataset, the value for the different type of performance measure using the pre-aggregated dataset; and providing the value for the different type of performance measure in response to the different request.