The schedule model development approach includes tasks such as:
Selecting data for:
- Creating activities
- Work Breakdown Structure (WBS)
- Activity duration
This data can be gathered in team meetings, BoQs (Bill of quantity), etc.
Further, we also choose:
- Schedule model presentation forms e.g. Gantt Chart, table, milestones, network diagram, simple list.
- Schedule life cycle type. Schedule Life cycles are explained here.
Various sources can be referred to for help when defining schedule development approach, explained here.
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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.
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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)
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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
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