20 Steps of Project Schedule Development Process Part - II



Step 6: Develop initial activity sequence independent of resource availability

Any project requires men, material, and machines to complete the schedule. These resources are not available for an indefinite period of time. Availability of resource is scarce and needs to be planned in order to achieve the deliverables. Resource availability affects the planned schedule and therefore should be taken into consideration while developing a schedule.

Step 7: Apply discretionary dependencies to address resource availability

In order to develop a realistic schedule consider the resource availability for each and every scheduled activity. A resource calendar is an important input to this step. Identify the working days and non working days for the project, establish the availability of resources in terms of skills, knowledge, geographical location, duration of availability of resources to the specific project.

Step 8: In order to determine duration of each activity consider availability and productivity of each resource

The information required is schedule activity scope of work, required resource types, estimated resource quantities and resource calendar with resource availabilities.

(a) Estimate the amount of work effort required to complete the schedule activity

(b) Estimate the amount of resources required to complete the schedule activity

(c) Determine the no of work periods required to complete the schedule activity

Parametric estimating and three point estimates are the most important estimating tools and techniques. Parametric estimating technique considers multiplying the quantity of work to be performed by the productivity rate. Three point estimates are based on determining the three types of estimates viz Optimistic, Pessimistic and Most likely.
Step 9: Include two mandatory milestones: Project Start & Project Finish

Project start and Project finish dates are two most important milestone that should be incorporated in a schedule. No schedule can ever be made with out these two critical milestones.
Step 10: Link each activity in the schedule and calculate early and late start and finish dates

Early Start (ES) and Early Finish (EF) helps in deriving the activity float ie the freedom available to move the start dates of the activity without delaying the project finish date. Early start date of activity is the earliest time an activity can start similarly early finish date is the earliest time an activity can finish. Technique used to calculate the ES and EF of an activity is called forward pass.

Late Start (LS) it is the latest time an activity can start without delaying the project Late Finish (LF) is the latest time an activity can finish without delaying the project. The technique used to find LS and LF is called backward pass.Calculation of ES/EF, LS/LF is the core of the network analysis and forms the basis of critical path analysis.

ES = EF of the immediate predecessor, for activities with more than one predecessor  it is the latest of the earliest finish times of the preceding activities.

EF = ES plus the activity duration

LS =  LF minus the activity duration

LF = LS of the activity that immediately follows, for activities with more than one activity that immediately follow, LF is the earliest of the LS of those activites.

Total Slack = LS – ES or LF – EF

Critical Paths have either a zero or negative total float/slack and it is the longest path in the schedule network between the start and finish dates

Total Float/Slack of an activity is the function of the performance of activities leading to it. It is shared by other activities.

Free Float/Slack is the amount of time that an activity’s earliest finish time can be delayed without delaying the earliest start time of any activities that immediately follows.

For Part I (Steps 1 to 5) click here
20 Steps of Project Schedule Development Process Part - II 20 Steps of Project Schedule Development Process Part - II Reviewed by AtulGaurPM on September 25, 2011 Rating: 5

No comments