Decision Feedback Equalization techniques are difficult to apply in high speed communications systems, as the decoding process for a received symbol may not be completed in time to allow adaptive detection of the following symbol. Advantage may be taken of certain novel aspects of vector signaling codes to provide decision feedback to an adaptive data receiver concurrent with symbol decoding, rather than being delayed to symbol decode completion. Methods and systems are described that error correct an initial non-adaptive decoding, based on differences between the actual received signals and simulated received signals derived from the initial decoding and historical received data. Additional methods and systems are described using bounding functions to estimate an error rate with reduced computation.