Switching Between Tools in Complex Applications
http://www.usabilityprofessionals.org/upa_publications/jus/2008august/schroeder1.html
  peer-reviewed

Schroeder, Will
Journal of Usability Studies
2008

Abstract:

Usability practice needs a procedure to identify, record, count, and highlight tool switch events for study. This paper describes one that supports the trained observers on which User-Centered Design relies to detect problems and causes, and evaluate design changes.