DGS/AVG is an Ultrasonic Flaw Detection technique that relates the amplitude of echoes from reflectors to that of a flat bottom hole at the same depth. It allows estimating the equivalent reflector size (ERS) of flaws. Traditionally, it involved manually comparing echo amplitudes to printed curves, but modern digital flaw detectors can automatically calculate the ERS by drawing curves based on the transducer's characteristics and a single calibration point. The technique accounts for beam spreading, material attenuation, and coupling variations to relate echo amplitudes to the size of circular disk reflectors, though it has also been applied to non-circular probes and elements.