1. A method for operating a programmable memory device, comprising: storing a value as a state in a first memory cell and as a complementary state in a second memory cell; determining the state of the first memory cell using a first self-biased sensing circuit and the complementary state of the second memory cell using a second self-biased sensing circuit; and comparing in a differential manner an indication of the state of the first memory cell to a reference indication of the complementary state of the second memory cell to determine the value, wherein the first memory cell is used in adjusting a reference voltage subsequently used in evaluating programmable states of memory cells of the memory device that do not have an associated complementarily-programmed memory cell.