In one embodiment, an encoder reads a set of data from memory cells to obtain retrieved data influenced by one or more distortion mechanisms as a result of having been stored. A quality metric is generated responsive to the retrieved data that changes in value responsive to differences between the user data and the associated retrieved data. A quality monitor establishes a relationship between a current value of the quality metric and a threshold value and monitors the relationship as being indicative of a degradation of the quality of the retrieved data, and selectively initiates an error response. In another embodiment, a correction value is iterated through a set of values as a quality metric is monitored such that the value of the quality metric which most closely approaches the value of the quality metric immediately subsequent to an initial writing of the data can be selected.