title: Mind the Gap: The Effect of Keyboard Key Gap and Pitch on Typing Speed, Accuracy, and Usability, Part 3.
abstract: OBJECTIVE
  The aim of this study was to evaluate the effects of key gap (distance between edges of keys) on computer keyboards on typing speed, percentage error, preference, and usability.
  
  
  BACKGROUND
  In Parts 1 and 2 of this series, a small key pitch (center-to-center distance between keys) was found to reduce productivity and usability, but the findings were confounded by gap. In this study, key gap was varied while holding key pitch constant.
  
  
  METHODS
  Participants (N = 25) typed on six keyboards, which differed in gap between keys (1, 3, or 5 mm) and pitch (16 or 17 mm; distance between centers of keys), while typing speed, accuracy, usability, and preference were measured.
  
  
  RESULTS
  There was no statistical interaction between gap and pitch. Accuracy was better for keyboards with a gap of 5 mm compared to a 1-mm gap (p = .04). Net typing speed (p = .02), accuracy (p = .002), and most usability measures were better for keyboards with a pitch of 17 mm compared to a 16-mm pitch.
  
  
  CONCLUSIONS
  The study findings support keyboard designs with a gap between keys of 5 mm over 1 mm and a key pitch of 17 mm over 16 mm.
  
  
  CONCLUSIONS
  These findings may influence keyboard standards and design, especially the design of small keyboards used with portable devices, such as tablets and laptops.
authors.affiliation: University of California, Berkeley.
authors.forename: Heather
authors.initials: H
authors.lastname: Madison
authors.affiliation: University of California, Berkeley.
authors.forename: Anna
authors.initials: A
authors.lastname: Pereira
authors.affiliation: University of California, Berkeley.
authors.forename: Mette
authors.initials: M
authors.lastname: Korshøj
authors.affiliation: University of California, Berkeley.
authors.forename: Laura
authors.initials: L
authors.lastname: Taylor
authors.affiliation: University of California, Berkeley.
authors.forename: Alan
authors.initials: A
authors.lastname: Barr
authors.affiliation: University of California, Berkeley david.rempel@ucsf.edu.
authors.forename: David
authors.initials: D
authors.lastname: Rempel
mesh_terms: D000328:Adult; D016287:Computer Peripherals; D004867:Equipment Design; D006804:Ergonomics / Q000295:instrumentation*; D005260:Female; D006801:Humans; D008297:Male; D008328:Man-Machine Systems
keywords: computer input devices; human–computer interaction; key cap; keyboard design