Misreads are considered to be among the more “dangerous” errors in check scanning. While a can’t-read simply generates an error, a misread substitutes one character for another — which can result in things like incorrect account numbers that are still valid; account balance problems, and other serious mistakes.
Substitution errors occur for many of the same reasons as can’t-reads, including out-of-spec magnetic printing or inconsistent feed rates. However, they occur far less frequently (it takes quite a bit of luck for an incorrect magnetic character to read correctly as another character; most of the time, it will simply cause an error). One of the most common MICR misreads is the substitution of a 2 for a 5 and vice versa, as those characters are close to mirror images of each other and the resulting magnetic waveforms are similar.