Short Reads Please turn javascript on. also see alignment Please turn the browser's JavaScript on. The error rate, ‘errRate’, is per position. errRate = length = output area key: #errs : Pr(#errs) {cummulative}, ..., e.g., for a rate of 1% and length of 30, 74% of reads have 0 errors, 22.4% have 1 error, and 3.3% have 2 errors.