1. A method in a computer for providing information about a current state that is modeled with multiple state attributes, comprising: identifying a first source that can supply a value for an indicated one of the state attributes of the modeled current state; identifying a second source that can supply a value for another of the state attributes of the modeled current state; and in response to receiving a request from a first client for a value of the indicated one attribute, wherein the request specifies a threshold level of accuracy of the value, determining that the first source is available to supply the value that exceeds the threshold level of accuracy; obtaining the value from the first source; before supplying the obtained value to the first client: determining whether the obtained value satisfies the threshold for value supplied by the first client; and when it is determined that the obtained value does not satisfy the threshold, requesting at least one additional source to supply the value for the one attribute that satisfies the threshold; receiving in response to the requesting at least one additional value for the one attribute that satisfies the threshold; and supplying to the first client a value for the one attribute based on the received additional value when it is determined that the obtained value does satisfy the threshold, supplying the value obtained from the first source to the first client.