The following missteps occur even in well-run companies with highly capable executives at the helm:

1. Lack of a clearly defined Integration Manager. 

Make sure one person is put in charge of the integration effort. Assigning individual accountability and responsibility is one of the best ways to make sure things get done. Some organizations choose one person from each organization to serve as co-leaders in the process. While this may seem equitable, it can lead to confusion as to who has formal sign-off over a given task or activity, or who is ultimately responsible for the success or failure of the transition effort. Generally, it’s a good idea to make sure that individuals from both organizations are present on the team, but it works best when only one person is in charge.

2. Failure to execute against plan. 

Transition teams often find it easier to develop a plan than execute one. The program for action should not be so complicated that it cannot be carried out. The role of the Integration Management Office is to ensure that the plan is manageable and that the integration teams do not become sidetracked...