Minimum String Distance

A metric for measuring text entry accuracy by calculating the minimum number of single-character insertions, deletions, and substitutions needed to transform the transcribed text into the intended text. In text entry research, the MSD error rate is typically expressed as a percentage: the minimum string distance divided by the maximum of the lengths of the intended and transcribed strings, multiplied by 100. Unlike KSPC (which counts all keystrokes including corrections), MSD measures only the errors remaining in the final output, making it a measure of the end result rather than the process. This metric is particularly important in evaluating assistive text entry systems where users may have difficulty detecting and correcting errors.