A method for checking position values using a monitoring unit to which position values of a position measuring device are supplied at time intervals of a query interval, includes: calculating a movement value from at least two position values and the time interval of their arrival; calculating an expected value for a position value to be checked that follows the at least two position values, by adding the most recent of the at least two position values and a change in position that results from the movement value and the time until the position value to be checked arrives; determining a position expectation interval from the expected value and a maximum position interval; comparing the position value to be checked to the position expectation interval; and outputting a signal that indicates the result of the comparison.