Definition

The time interval between the senso­ry perception of a PHENOMENON and the motor reaction thereto. Personal equation may be either positive or negative, as an observer may anticipate the occurrence of an event, or wait until he actually sees it occur before making a record. This is a SYSTE­MATIC ERROR, treated as of the constant type. It is a PERSONAL ERROR, for which the term personal equation is reser­ved. It is of special significance in OBSERVA­TI­ONS of TIME, made to determine CHRONOMETER CORREC­TION.