to read a plurality of memory cells , each cell is assigned to a respective cell population . a respective value of an operational parameter of each cell is measured . each cell is assigned an a - priori metric based at least in part on one or more cvd parameter values of the cell &# 39 ; s population . the a - priori metrics are decoded . based at least in part on the resulting a - posteriori metrics , the cvd parameter values are corrected , without repeating the measurements of the cell operational parameter values . the operational parameter values are indicative of bit patterns stored in the cells , and the correction of the cvd parameter values is constrained by requiring the bit patterns collectively to be a valid codeword .