Why Is It So Successful?

There are several factors that make interim management the powerful resourcing option that it has become today:

Speed - Interim managers can be in place within days as opposed to weeks (essential when time constraints are paramount).
Experience - Interim managers will be more than qualified for the position they are taking on and will therefore be stepping down in responsibility. They will also have past experience of similar challenges to the ones they are about to face. In addition to enabling them to have an immediate effect and be productive from the outset, this minimises the risk of things going wrong and, more importantly, ensures success.
Objectivity - Unencumbered by any previous involvement in company processes or staff relationships, interim managers provide a fresh perspective and are free to concentrate on what's best for the business.
Accountability - Rather than taking on a purely advisory role (as a management consultant would), interim managers are responsible and accountable line managers who will implement and manage a business or project in their own right.
Effectiveness - Operating at or near board-level gives interim managers the authority to effect significant change or transition within a company unlike a temp, they're not just there to hold the fort.
Commitment - Interim managers are committed to an interim career. For them, this is never just something they are doing until a suitable permanent position is found. They enjoy the challenge of the different assignments, take great pride in maintaining the highest standards and realise that they are only ever as good as their last job.