Estimate Activity Durations Explained
Estimate Activity Durations is a critical process in project management that involves determining the number of work periods needed to complete individual activities with estimated resources. Accurate duration estimates are essential for creating a realistic project schedule and ensuring that the project stays on track.
Key Concepts
1. Activity List
The Activity List is a comprehensive list of all the activities required to complete the project. It includes a brief description of each activity and is derived from the Work Breakdown Structure (WBS). The Activity List is the foundation for estimating the duration of each activity.
Example: For a software development project, the Activity List might include activities such as "Design User Interface," "Develop Backend Logic," and "Perform Unit Testing." Each of these activities will be estimated for duration.
2. Activity Attributes
Activity Attributes provide additional information about each activity in the Activity List. This includes details such as predecessors, successors, resource requirements, and constraints. Understanding these attributes helps in making more accurate duration estimates.
Example: In a construction project, the Activity Attribute for "Install Windows" might include information about the required number of workers, the availability of materials, and the dependency on the completion of "Frame Walls."
3. Resource Requirements
Resource Requirements refer to the types and quantities of resources needed to complete each activity. This includes human resources, equipment, materials, and budget. Estimating the duration of activities is closely tied to the availability and efficiency of these resources.
Example: For a marketing campaign, the resource requirements for the activity "Create Promotional Videos" might include a video production team, cameras, editing software, and a budget for hiring actors. The duration estimate will depend on the availability and skill level of these resources.
4. Duration Estimating Techniques
Duration Estimating Techniques are methods used to calculate the time required to complete activities. These techniques include Analogous Estimating, Parametric Estimating, and Three-Point Estimating. Each technique has its own advantages and is suited to different types of projects.
Example: Analogous Estimating might be used for a new construction project by comparing it to a similar past project. Parametric Estimating could be used for a software development project by calculating the time based on the number of lines of code. Three-Point Estimating involves calculating the most likely, optimistic, and pessimistic durations to arrive at a weighted average.
5. Project Schedule Network Diagrams
Project Schedule Network Diagrams illustrate the sequence of activities and their dependencies. These diagrams help in visualizing the project timeline and understanding how the duration of one activity can impact others. This is crucial for making informed duration estimates.
Example: In a project to develop a new product, the network diagram might show that the activity "Prototype Testing" cannot start until "Design Prototype" is completed. Understanding this dependency helps in estimating the duration of "Prototype Testing" more accurately.
6. Risk Management
Risk Management involves identifying, assessing, and mitigating risks that could impact the duration of activities. Incorporating risk factors into duration estimates helps in creating a more realistic and resilient project schedule.
Example: For a project to launch a new website, potential risks such as technical issues or delays in content creation could be factored into the duration estimates for activities like "Develop Website" and "Content Creation."