Using primavera to calculate the forward pass and backward pass dates of a project. There are various ways to calculate the late start and late finish dates of a project.

1. AMIT
8th October’2017
Primavera |Amit Kumar Senapati
PLANNING
USING FORWARD PASS AND
BACKWARD PASS IN PRIMAVERA

2. USING FORWARD AND BACKWARD PASS IN PRIMAVERA
INTRODUCTION
Forward pass is a technique to move forward through a diagram to calculate activity duration.
Backward pass is its opposite. Early Start (ES) and Early Finish (EF) use the forward
pass technique. To determine the Early Start of an activity, factor in all its dependencies and
see its earliest start date.
The forward pass begins at either the start date of a project (if there is no progress reported) or
the data date of the project and goes forward in time taking into consideration the durations,
calendars, logical ties and any hard constraint dates. This will determine the EARLIEST that an
activity can start and or finish. These are the early dates.
The backward pass begins at the project must finish by date (if no constraint date is used then
it starts at the early finish date) and goes backward in time taking into consideration the
durations, calendars, logical ties and any hard constraint dates. This will determine the LATEST
that an activity can start and/or finish. These are the late dates.
The difference between the late date and the early dates is the float.

3. USING FORWARD AND BACKWARD PASS IN PRIMAVERA
USE OF PRIMAVERA TO FACILITATE BACKWARD AND FORWARD PASS
Step 1:
Let us consider a project, with the following assumptions:-
a) All the activities have the correct relationship.
b) Correct calendar has been used for the project.
c) The activity name and duration is correct.
d) The current completion of activity ID DUC-BSD-CRA-016 is 13th
Feb’18. Highlighted
e) The targeted completion of activity ID DUC-BSD-CRA-016 must be 10th
Jan’18. Highlighted
STEP 2: There are two ways by which we will be able to find the Backward pass
and forward pass dates.
a) By using project constraints under the status tab. One of the benefits of
using project constraints is that we can do the calculation on the basis of an
activity constraint for any particular activity.
b) By assigning a project must finish date under date tab, using the project
view.

4. USING FORWARD AND BACKWARD PASS IN PRIMAVERA
Here we have constraint of
completing the activity on or before
10th
Jan 18
Include column Early Start, early
finish, late start and late finish
Conclusion:
From the above example the forward pass dates is determined by using the Early Start and Early Finish
Dates and the backward pass dates is determined by using the Late Start and Late Finish Dates.
As we have used the constraints, the float of some of the activities is negative. So, in this case the team
needs to re-plan to bring the total float of activities to zero or greater than that.
The total float for some of the activities is negative, which gives an indication on the current delay of
the project.