Methods and apparatus are provided for soft data generation for memory devices based on a performance factor adjustment. At least one soft data value is generated for a memory device, such as a flash memory device, by obtaining at least one read value; and generating the soft data value based on the obtained at least one read value and an adjustment based on one or more performance factors of the memory device. The read values may be soft data or hard data. Possible performance factors include endurance, number of read cycles, retention time, temperature, process corner, inter-cell interference impact, location and a pattern of aggressor cells. One or more pattern-dependent and/or location-specific performance factors may also be considered. The generated soft data value may be a soft read value used to generate one or more log likelihood ratios or may be the log likelihood ratios themselves.