One particular implementation conforming to aspects of the present invention takes the form of a method for tracking the stability of a data set for multiple observers. More particularly, a tracker object may be used to both mark a particular state of the data and to query if the data remains unchanged. Code that accesses the data set to calculate a result may fetch a reference to a current tracker object associated with the data set. The code may compare the current tracker object received from the data set against the tracker object associated with the last cached result. In an alternate arrangement, a state may be associated with the data set to indicate some characteristics of the data set. The state value associated with the data set may further simplify the action required by a code accessing the data set to receive an accurate calculation.