The duration of a project, as stated by Wysocki (2012), refers to the elapsed time in business working days, excluding weekends, holidays, or other non-work days.
Estimating task duration poses a challenge for project teams, lacking fixed rules or clear assumptions. It involves task resource allocation and may vary across individuals and projects (Wysocki, 2012).
Wysocki (2012) identifies six methods for estimating project duration:
- Similarity to other activities: Used when two similar projects exist, enabling estimation based on the completed project’s task duration and lessons learned.
- Historical data: Common in construction projects, where actual productivity rates from completed projects are recalled to estimate task duration.
- Expert advice: Sought for new tasks or those requiring special arrangements, as in cases where unique expertise is needed for accurate estimation.
- Delphi technique: Utilized when expert advice is unavailable, involving a group of participants to provide opinions on task duration, with subsequent refinement through multiple passes.
- Three-point technique: Considers task duration as a random variable, combining historical data with optimistic, pessimistic, and most likely scenarios to estimate duration.
- Wide-band Delphi technique: A fusion of Delphi and Three-Point techniques, where participants provide estimates for optimistic, pessimistic, and most likely scenarios, with averages calculated accordingly.
Resource-driving tasks, such as erecting mega roof steel and glass panels, pose a unique challenge as they rely solely on resource productivity rates, rendering traditional estimation methods ineffective.
In such cases, task duration is calculated based on resource productivity: Task duration = (Panels Quantity) / (Tower crane productivity per day * number of tower cranes).
These methods provide a comprehensive framework for estimating project duration across various scenarios and project types, ensuring accurate planning and execution.
References:
Wysocki, R. K. (2012). Effective Project Management: Traditional, Agile, Extreme (6th ed.). John Wiley & Sons.
