The more targets there are to scatter the pulse, the stronger the return will be because the return signals from each target combine to produce a stronger signal. This means that many large raindrops will produce a stronger return than a few small raindrops. The quantity that a radar measures is the returned power which, with knowledge of other radar characteristics, is converted to a quantity called the reflectivity factor, or more simply, the "reflectivity".
The magnitude of the reflectivity is related to the number and size of the drops encountered by the electromagnetic pulse. For this reason, high reflectivity generally implies heavy precipitation while low reflectivity implies lighter precipitation. Plots of the radar reflectivity, typically using colors to depict its magnitude, show both the location and intensity of precipitation. Extremely high reflectivities often indicate hail.