TO VERIFY THE USEFULNESS OF SABER DATA FOR TRENDING WE MONITOR PERFORMANCE CHARACTERISTICS THAT WOULD INDICATE CHANGE IN THE LONG-TERM STABILITY OF THE SABER RADIOMETRIC CALIBRATION. THE MOST IMPORTANT CALIBRATION AFFECTING TRENDS IS ABSOLUTE RESPONSE STABILITY WHICH IS MONITORED BY TRACKING THE RADIANCE-PER-COUNT SCALE FACTOR AS A FUNCTION OF TIME. THIS QUANTITY IS OPERATIONALLY MONITORED BY ALTERNATELY VIEWING SPACE (COLD POINT) AND THE INSTRUMENT IN-FLIGHT CALIBRATOR (IFC) (WARM POINT). THE TWO MOST IMPORTANT ERROR CONTRIBUTORS ARE CHANGES IN IFC BLACKBODY EMISSIVITY AND DRIFT IN THE ELECTRONIC CIRCUITRY USED TO MONITOR THE IFC TEMPERATURE. THE TEMPERATURE MONITOR DRIFT IS PREDICTED FROM PRE-LAUNCH INFORMATION TO BE VERY SMALL (<0.02K). THE TOTAL SCALE FACTOR CHANGES LINEARLY FIT OVER THE LIFE OF THE MISSION ARE SHOWN IN FIGURE 1 FOR ALL CHANNELS IN TERMS OF CHANGE RELATIVE TO THE BEGINNING OF THE MISSION.