Calculate earliest finish time of each activity that begins at event (i) . This is equal to the earliest start time of the activity plus the duration of the activity (I.e) EFij = ESij + tij = Ei + tij, for all activities (i,j) beginning at event i.

Earliest Occurrence Time (EOT) The EOT of an event is the duration of the longest path (from beginning event whose EOT is set at 0) leading to that event. Hence, EOT of the end event represents the minimum time required for completing the project.

Earliest Event Time – The earliest event time represents the earliest time an event can possibly begin; conventionally, it is zero for the first event.

Since the difference between the latest Start time & earliest start time of an activity is usually called as total float.

The formula used for calculating Early Start and Early Finish dates:

1. Early Start of the activity = Early Finish of predecessor activity + 1.
2. Early Finish of the activity = Activity duration + Early Start of activity – 1.

We can consider (i) Earliest Expected Time of Occurrence of an event and (ii) Latest Allowable Time of Occurrence an event. The Earliest Expected Time of Occurrence of an event is the earliest possible time of expecting that event to happen on the condition that all the preceding activities have been completed.

PERT vs CPM The difference between PERT and CPM is that PERT stands for Program Evaluation and Review Technique, and CPM stands for Critical Path Method. PERT manages unpredictable activities, whereas CPM manages predictable activities. PERT is related to the events, but CPM is related to the activities.

PERT is that technique of project management which is used to manage uncertain (i.e., time is not known) activities of any project. CPM is that technique of project management which is used to manage only certain (i.e., time is known) activities of any project.

[¦ər·lē·əst ′start ‚tīm] (industrial engineering) The earliest time at which an activity may begin in the schedule of a project; it equals the earliest time that all predecessor activities can be completed.

Early Start represents the earliest date an activity can possibly begin, based on all its predecessors and successors. Early Finish represents the earliest date an activity can possibly finish, if all predecessors and successors also finish on their respective early finish dates.

Formulas for calculating Total Float and Free Float are as follows:

1. Total Float = LS – ES (it is also calculated by LF – EF)
2. Free Float = Lowest ES of successors – EF.

The earliest time for completion of an activity of a project; for the entire project, it equals the earliest start time of the final event included in the schedule.

The early start of the project is declared first. Unless we have at least one date that tells where the project begins or ends, it will be possible to know the schedule only relative to other activities. Normally we want to know the project schedule relevant to real calendar days over a specific period of time.

Both CPM and PERT are network based techniques. They are vital tools in the planning, scheduling, and control of projects. A project is a collection of interrelated activities with each activity consuming time and resources. In order to use either method you must: (1) Define the activities involved for each project.

The early finish of an activity is the early start of the activity plus the duration minus one. In the case of the early schedule, the early start of the successors of any activity is the beginning of the next time period after the completion of the preceding activity.

Tasks like a morning jog, eating breakfast, taking a shower, and getting dressed are activities which must be completed in order to complete the project. This is project planning in its simplest form. Whether we do it mentally or use pen and paper, we plan for every project in an effort to save time, money, and avoid headaches.