Predecessor refers to the network analysis, which determines which of the activities can be successor or predecessor. The predecessor event is an event that must be completed before a specified activity can begin. The dependency between two activities is thereby described. Generally, an activity needs a time period with the determined start and end date. These dates are displayed in the network. There are available different sequences of successor and predecessor in the network: start-to-end, with other words the activity can start, if its predecessor is completed; end-to-end, an activity is completed, if its predecessor is completed; end-to-start, an activity is completed, before its predecessor begins.
It is very important to preserve the logical relationship in the network. As a basis for the running project control and the deadline monitoring this plan provides an overview about the critical activities that can delay the whole project. The slacks that defined as reserves are also integrated in the network. One of the types of such reserves is an independent slack that is a maximal time delay of one activity where all previous activities are completed until the latest possible date and all following activities should start until the earliest possible date. This slack influences therefore neither predecessors nor successors and the dependencies are kept.