1. A computer-implemented method for cleaning television viewing data by detecting and correcting a set top box buffer overflow, the method comprising: accessing television viewing data transmitted from a set top box; determining a time threshold indicative of a buffer overflow for the set top box; calculating a duration that has elapsed between the last television viewing datum logged by the set top box in the accessed television viewing data and the time when the television viewing data was transmitted from the set top box; if the calculated duration exceeds the determined time threshold, then correcting the television viewing data for a set top box buffer overflow; and if the calculated duration does not exceed the determined time threshold, then not correcting the television viewing data for a set top box buffer overflow.