Proofreading Error Rates
Spirrison and Gordy (1993) found 193 undergraduate students had an average error rate of 24% when proofreading a 385-word passage with 49 seeded errors. This means, on average, undergraduates missed 12 of the 49 seeded errors. Using various populations, other researchers found error rates from 5-58% when asking subjects to find wrong words and/or nonwords in a predetermined text (Cohen, 1980; Daneman & Stainton, 1993; Dittmer, 1994; Healey, 1980; Levy, 1983; Levy & Begin, 1984; Levy, Di Persio, & Hollingshead, 1992; Riefer, 1991, Wallace, 1991). Since no such studies have been conducted using solely professional editors as subjects, we must turn to anecdotal evidence and rules of thumb from non-academic sources. The average error rate for professional editors has been stated to be 1-5% or more (Shipton, 2011; Montgomery, 2013). With proofreading tools and trained doctoral-level editors reading each text twice, WordSharp has achieved an error rate of less than 1%.
Cohen, G. (1980). Reading and searching for spelling errors. In U. Frith (Ed.), Cognitive processes in spelling (pp. 135-155). London, UK: Academic Press.
Daneman, M., & Stainton, M. (1993). The generation effect in reading and proofreading: Is it easier or harder to detect errors in one's own writing? Reading and Writing: An Interdisciplinary Journal, 5, 297-313.
Dittmer, M. L. (1994). Proficiency and workload in simultaneous and successive proofreading tasks. Journal of General Psychology, 121(4), 319-332.
Healey, A. F. (1980). Proofreading errors on the word: The new evidence on reading units. Journal of Experimental Psychology: Human Perception and Performance, 6(1), 45-57.
Levy, B. A. (1983). Proofreading familiar text: Constraints on visual processing. Memory & Cognition, 11(1), 1-12.
Levy, B. A., & Begin, J. (1984). Proofreading familiar text: Allocating resources to perceptual and conceptual processing. Memory & Cognition, 12(6), 621-632.
Levy, B. A., Di Periso, R., & Hollingshead, A. (1992). Fluent reading: Repetition, automaticity, and discrepancy. Journal of Experimental Psychology: Learning, Memory, and Cognition, 18(5), 957-971.
Montgomery, A. (2013). Error rates in editing. Retrieved from https://www.copyediting.com/error-rates-in-editing/
Riefer, D. M. (1991, December). Behavioral engineering proposals: 4. Is "backward reading" an effective proofreading strategy? Perceptual Motor Skills, 767-777.
Shipton, R. (2011). The mysterious relationship: Authors and their editors. In D. Cullen (Ed.) Editors, Scholars, and the social text. Toronto, Canada: University of Toronto Press.
Wallace, B. (1991). Imaging ability and performance in a proofreading task. Journal of Mental Imagery, 15(3-4), 177-188.