Fact · Typing and writing speed
In the 2018 study, the uncorrected error rate was the Levenshtein edit distance between the presented and transcribed strings, divided by the length of the longer string.
Checked against its source on October 16, 2026
In the source's own words
“UNCORRECTED ERROR RATE is calculated as the Levenshtein edit distance [23] between the string presented and the ... divided by the larger number of characters between the two strings.”
Observations on Typing from 136 Million Keystrokes, Vivek Dhakal et al., CHI 2018, ACM Conference on Human Factors in Computing Systems, 2018, Performance Measures.
Open the original (DOI 10.1145/3173574.3174220)- What it measures
- The minimum string distance (MSD) in the 2003 CHI paper is the same kind of count: the fewest insertions, deletions and substitutions that turn one string into the other.
- What it does not show
- The rate measures what is left in the final text, so typos that were fixed before the sentence ended do not count.