Change management studies 
Can change management really make a difference during your Google Apps deployment? Yes! Check out some of the evidence....
A McKinsey study showed a significantly higher return on investment (ROI) for projects with change management:
  • 143% ROI for projects with excellent change management
  • 35% ROI for projects with poor or no change management
Research organization Prosci showed a strong correlation between change management effectiveness and meeting project objectives, staying on schedule and staying on budget.

IBM found that leadership, employee engagement and communications were prerequisites for successful IT changes.

A study in the journal Darwin, entitled "Six Ways IT Projects Fail," revealed the reasons IT projects fail, including:
  • Lack of executive sponsorship
  • Unrealistic expectations 
  • Poor or dishonest communication
Sources

[1] “Change Management That Pays,” McKinsey Quarterly, 2002.
[2] Integrating, People, Process and Technology. by Anton, Petouhoff and Schwartz, Santa Maria, CA: The Anton Press, 2003.
[3] Boston Consulting Group. (2003). Research study. In Integrating, People, Process and Technology. by Anton, Petouhoff and Schwartz, Santa Maria, CA: The Anton Press, 2003.
[4] Ulfelder, Steve. (2001). “Six Ways I.T. Projects Fail And How You Can Avoid Them.” Darwin magazine. Retrieved June 2001, http://www.darwinmag.com/read/060101/dirty.html.
[5] Myron, David. (2003). “6 Barriers to CRM Success And How to Overcome Them.” DestinationCRM.com, August. Retrieved from http://www.destinationcrm.com/articles/default.asp?articleid=3316.
[6] “Software Disasters Are Often People Problems.” Retrieved Tuesday, October 5th, 2004, CNN.com.
[7] Research study by Bain Consulting Group. Integrating, People, Process and Technology. by Anton, Petouhoff and Schwartz, Santa Maria, CA: The Anton Press.
[8] Ibid. Research study by Forrester Group.
[9] ProSci. (2003). “Best Practices in Change Management.”
[10] AMR Research Report, 2003.
[11] Change Management Case Studies, Hitachi Consulting.