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Project Management Orientation

Bottom-Up Estimating 

Bottom-up estimates are the cost and duration of individual work items in hours, which is summarized or combined, resulting in a project total.  The cost and accuracy are driven by the size of the individual work items.  Smaller work items increase both cost and accuracy to the project estimate. 
  
Bottom-up estimates are considered to be the most accurate and allow for the integration of activities that occur within an organization.  A good bottom-up estimate demonstrates a detailed understanding of the work to be done on a project.
  
A key challenge of these estimates is that people providing the estimates might add reserve to individual activities.  That is why a project manager must explain to the team that the LOE, availability, and productivity have been included in the estimate for individual tasks.  The bottom-up approach is the financial equivalent of the scientific method of discovery.  Where the scientific method takes the whole and decomposes it to its smallest parts, the bottom-up method assigns estimates to the smallest parts and then composes them back to the whole.

Estimation Methods

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description of that term.

Parametric Estimate
Analogy or Comparison Estimating
Expert Judgment Estimating
Top-Down Estimating
Bottom-Up Estimating
1: Getting Started
2: Define the Project Team
3: Team Management
4: Identify and Validate Requirements
5: Create Decomposition Structures
6: Risk Management
7: Project Estimates
8: Project Schedules
9: Change Management
10: Project Control and Execution
Defining the Project
11: Project Management Review
12: Project Closeout
13: Project Management Tool Suite
14: Self-Assessment and Final Exam
Fast Points
Concepts
Seven Keys
Case Study
WWPMM
Mentor
Check Point
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