What is the role of a scheduler? Scheduler performs many tasks. The tasks he will do will be assigned to him by a project manager. His tasks could include:

  • Gathering schedule data (milestones, activities and their attributes e.g. dates, except risk activities)

  • Attending meetings to discuss schedule, format, reporting format.

  • Revising schedule.

  • Update plan with actual progress of activities, resources productivity rates.

  • Analysis of plan and actual progress.

  • Analyzing critical path

  • Perform resource leveling

  • Creating reports of plan, actual and forecasted schedule.

  • Creating Work Breakdown Structure (WBS)

  • Creating Organizational Breakdown Structure (OBS)

  • Creating Resource Breakdown Structure (RBS)

Analogous estimation technique:

It is a comparison technique where we look at a similar activity performed before. If more data is available, the better the estimate will be.

Parametric estimation technique:

Parameters from previous similar activity is taken. E.g. Previous activity took 5 days and it had 3 resources working on it, 10 hours daily. This method is more accurate then analogous estimation

Three-point estimation technique

It is used when there is a great deal of uncertainty about duration. We use these parameters and use in the formulas below.


M = most likely | O = optimistic | P = pessimistic | E = expected duration

  • Triangular Distribution:       E = (P + M+ O) / 3
  • Beta Distribution (also called PERT - Program evaluation and review technique):      E = (P + M(4) + O) / 6


Beta Distribution is preferred in cases where we have a lot of historical data.  When there is no historic data, only with guesses, use Triangle Distribution.

Using these duration estimation techniques, you can get near-to-accurate duration value. It is much better than just guessing a wrong duration, which will negatively effect the project end date

Activities are work to be performed. The project activities have the following characteristics:

Activity owner: a single person accountable for its performance. That person also reports progress on the activity.


Activity description: Name like ‘pour wall’ is self explanatory but some detail should be added such as ‘pour the east wall from top to bottom’.


Continuity of activity: Activity should represent continuous work. If any break to be added in activity, it is better to split the activity from breakpoints. 

Activity Start and Finish dates.

Activity Duration: Ideally, activity duration should be less than two times the update cycle. For example schedule is updated after every 10 days. The activity duration should be 5 or less. 

  • This is to allow reporting of the start and finish of the activity within one or two update cycles. 
  • This helps the management to focus on performance.
  • This is not applicable on Summary, Level-of-Effort (LoE) and Hammock activities.

Critical path is identified with the use of Critical Path Method (CPM), which involves identifying:

  • Activity duration

  • Activity relationships (any relationship i.e. SS, FF, FS, SF)

  • Activities with zero Total Float (activities which can’t be delayed. If delayed, project end date will be effected)

This resultant critical path gives us the following:

  • Longest path (longest set of activities) in the project. In other words it gives us project duration
    Project end date.

  • Critical Path activities (activities that fall on Critical Path which also have zero Total Float)
    Early and Late dates of activities (detail in next slide)

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