The executive makes a “vendor” or external “coach” responsible for the transition
If you have handled the first risk and have defined success and success metrics, you likely will not find a vendor who will base his payment on your metrics. After all, the metrics likely call for less project failure rate, faster response times, etc. You probably can’t measure these things in less than a year if you really want objective metrics and not one optimized for short-term results at the expense of the longer term. A vendor might want:
# of people trained
% of teams using an “agile” project management tool
# of teams with an embedded “agile champion”
# of successful iterations
It is really easy to accomplish the above metrics and still not make any material change in the organization. I have worked with a client that did something similar to the above. Most of the teams starting using some new Scrummy project management web application for project tracking. They declared that monthly status meetings were now iterations. They declared a member of the team to be the Scrummaster (and sent that person to training). Overall, the same organizational problems persisted. Vendors cannot produce real change in an organization unless the organizations executive leadership alters the culture in a meaningful way.