Action item tracking can help to make sure that things do not "fall through the cracks". It is one of the potential processes and procedures that may be provided by the organizational process assets. It is a way of tracking needed actions that are not well tracked as part of the project activities in the work breakdown structure. The action items are usually shorter in duration than the activities or may involve a person that performs only one act as part of a larger activity.
An action item list is a useful tool for tracking action items.