A method for calibrating an estimated gaze location of a viewer of a display device, the method comprising: monitoring the estimated gaze location of the viewer using gaze tracking data from a gaze tracking system during a target timeframe and at a plurality of instances; receiving , from a content source via a calibration application programming interface, image data including at least one target visual for display via the display device, wherein the image data comprises a video , the at least one target visual traverses a predetermined path comprising target locations during the target timeframe and attracts a gaze of the viewer , and the image data comprises target visual metadata that identifies the at least one target visual in the video , and receiving , from the content source via the calibration application programming interface, a probability that the viewer is gazing at the target locations ; without using input from the viewer , identifying within the image data the at least one target visual ; without using input from the viewer , using the target visual metadata to identify the target locations of the at least one target visual ; comparing the estimated gaze locations of the viewer with the target locations of the at least one target visual at the plurality of instances during the target timeframe; calculating an offset vector for each comparison based on the estimated gaze location and the target location ; and calibrating the gaze tracking system using the offset vectors to generate updated estimated gaze locations of the viewer , wherein an offset vector is excluded from the other offset vectors in calibrating the gaze tracking system based on combining the probability with the offset vector exceeding a predetermined threshold offset value. monitoring the estimated gaze location of the viewer using gaze tracking data from a gaze tracking system during a target timeframe and at a plurality of instances; receiving , from a content source via a calibration application programming interface, image data including at least one target visual for display via the display device, wherein the image data comprises a video , the at least one target visual traverses a predetermined path comprising target locations during the target timeframe and attracts a gaze of the viewer , and the image data comprises target visual metadata that identifies the at least one target visual in the video , and receiving , from the content source via the calibration application programming interface, a probability that the viewer is gazing at the target locations ; without using input from the viewer , identifying within the image data the at least one target visual ; without using input from the viewer , using the target visual metadata to identify the target locations of the at least one target visual ; comparing the estimated gaze locations of the viewer with the target locations of the at least one target visual at the plurality of instances during the target timeframe; calculating an offset vector for each comparison based on the estimated gaze location and the target location ; and calibrating the gaze tracking system using the offset vectors to generate updated estimated gaze locations of the viewer , wherein an offset vector is excluded from the other offset vectors in calibrating the gaze tracking system based on combining the probability with the offset vector exceeding a predetermined threshold offset value. <EOS>