Rate or Daily rate is the amount of time (in seconds or minutes) by which the movement of a test watch differs from that of a reference watch. The decisive factor is the regularity, ie at a daily measurement the difference per day must always be identical. If the watch is 10 seconds faster at the end of each testing day, the rate is 10 seconds.
It is important that the watch is always measured under the same conditions (temperature, position) of the rate measurement, otherwise there will be rate deviations which don't have their cause in the movement itself.
The measurement can be performed with a timegrapher or with special programs for long-term observation. In the simplest case, one registers the transition with paper, pencil and a radio-controlled watch as reference.
See also: Precision adjustment