1. An apparatus, comprising: an array of resistance variable memory cells; and circuitry configured to: apply a programming signal to a memory cell in the array continuously for a particular time period, wherein the memory cell had previously been programmed to one of a number of data states and the programming signal is a signal that is also used to program resistance variable memory cells to a particular data state of the number of data states; and determine a data state of the memory cell by comparing a first signal associated with an electrical characteristic of the memory cell generated during the particular time period while applying the programming signal to the memory cell and a second signal associated with the electrical characteristic of the memory cell generated during the particular time period while applying the programming signal to the memory cell, wherein the data state of the memory cell is the particular data state when the first signal is equal to the second signal and the data state of the memory cell is different than the particular data state when the first signal is different than the second signal.