Cost Estimation & Control

Top Down Cost Estimating

Top-Down Cost Estimating: A Bird's Eye View for Project Success

Cost estimation is a critical aspect of any project, determining its feasibility, resource allocation, and overall success. While numerous methods exist for estimating costs, the "top-down" approach stands out for its rapid and high-level assessment, often employed in the initial stages of project planning.

What is Top-Down Cost Estimating?

Top-down cost estimating, as the name suggests, starts with a "big picture" perspective. It utilizes experience and judgment to arrive at an overall cost estimate for the project. Rather than meticulously breaking down the project into its smallest components, the top-down approach relies on:

  • Historical data: Comparing the current project to similar projects undertaken in the past.
  • Expert opinion: Drawing upon the expertise of experienced estimators or managers to provide a subjective assessment.
  • Analogous estimating: Utilizing existing cost data from comparable projects as a starting point.

Key Characteristics of Top-Down Cost Estimating:

  • Speed and efficiency: Provides a quick and rough estimate, suitable for initial planning and budgeting.
  • Simplicity: Requires minimal detailed information and can be carried out with readily available data.
  • Subjectivity: Relies heavily on the experience and judgment of the estimator, making it prone to biases.
  • Accuracy limitations: Offers a general range, but lacks the detailed precision of bottom-up methods.

Applications of Top-Down Cost Estimating:

  • Early project feasibility assessment: Quickly determining if a project is financially viable.
  • Budget planning and resource allocation: Providing a preliminary framework for budget allocation and resource management.
  • Proposal development: Establishing a baseline cost for proposal development and client negotiations.
  • Preliminary cost comparisons: Comparing various project options based on rough cost estimates.

Advantages of Top-Down Cost Estimating:

  • Time-saving: Offers quick and efficient cost estimations for initial planning.
  • Cost-effective: Minimal resources required for data collection and analysis.
  • Simplicity: Easy to understand and implement, even with limited project details.

Disadvantages of Top-Down Cost Estimating:

  • Accuracy limitations: Prone to significant errors due to subjective judgment and limited data.
  • Bias potential: Can be influenced by the estimator's previous experience and personal biases.
  • Lack of detail: Fails to capture detailed cost breakdowns for individual project components.

Conclusion:

Top-down cost estimating is a valuable tool for initial project assessment and planning. Its strengths lie in its speed and simplicity, making it ideal for early stage feasibility studies and budget allocation. However, it's crucial to acknowledge its limitations in terms of accuracy and detail. By complementing top-down estimates with more detailed bottom-up methods, project managers can achieve a more robust and reliable cost assessment for their endeavors.


Test Your Knowledge

Quiz on Top-Down Cost Estimating:

Instructions: Choose the best answer for each question.

1. What is the primary characteristic of top-down cost estimating? a) Detailed breakdown of project components b) High-level assessment based on experience and judgment c) Extensive data analysis and modeling d) Precise cost estimates for each task

Answer

b) High-level assessment based on experience and judgment

2. Which of the following is NOT a key characteristic of top-down cost estimating? a) Speed and efficiency b) Simplicity c) Objectivity d) Subjectivity

Answer

c) Objectivity

3. Top-down cost estimating is most suitable for: a) Detailed project budgeting b) Initial project feasibility assessment c) Final project cost reporting d) Measuring project progress

Answer

b) Initial project feasibility assessment

4. What is a major disadvantage of top-down cost estimating? a) Requires extensive data collection b) Prone to significant errors due to subjective judgment c) Requires highly skilled estimators d) Time-consuming and complex

Answer

b) Prone to significant errors due to subjective judgment

5. When is top-down cost estimating most beneficial? a) When precise cost estimations are critical b) When detailed project plans are unavailable c) When historical data is incomplete d) When extensive resource allocation is required

Answer

b) When detailed project plans are unavailable

Exercise on Top-Down Cost Estimating:

Scenario: You are tasked with providing a preliminary cost estimate for developing a mobile app. You have limited information about the app's features and functionalities.

Task: Using the principles of top-down cost estimating, provide a rough estimate for the app development cost. Explain your reasoning and consider factors like historical data, expert opinion, and analogous estimating.

Exercice Correction

**Reasoning:** * **Historical data:** Research the average cost of developing similar mobile apps. Consider factors like app complexity, platform (iOS/Android), and development team size. * **Expert opinion:** Consult with experienced mobile app developers or project managers to get their subjective assessment of the cost based on your initial description of the app. * **Analogous estimating:** Use cost data from comparable projects you've worked on in the past or that are publicly available. **Estimate:** Based on the above factors, you can provide a range of costs for the app development. For example, you could estimate the cost to be between $20,000 and $50,000. Remember, this is a rough estimate and will be refined as you gain more information about the project. **Justification:** Explain your rationale for the estimated range based on the factors considered above. For example, if you've found that similar apps cost $30,000-$40,000 on average and the expert opinion suggests a slightly higher cost due to the complexity of your app, you could justify the range of $20,000-$50,000.


Books

  • Project Management Institute (PMI). (2017). A Guide to the Project Management Body of Knowledge (PMBOK® Guide) (7th ed.). Project Management Institute.
    • This comprehensive guide covers various aspects of project management, including cost estimation, and provides an overview of different methods, including top-down estimating.
  • Kerzner, H. (2017). Project Management: A Systems Approach to Planning, Scheduling, and Controlling (11th ed.). John Wiley & Sons.
    • Another widely recognized project management text that provides insights into cost estimation techniques, including top-down approaches.
  • Cleland, D. I., & Ireland, L. R. (2016). Project Management: Strategic Design and Implementation (7th ed.). McGraw-Hill Education.
    • This book delves into project management principles and offers a practical understanding of cost estimating, including top-down methods.

Articles

  • "Top-Down Cost Estimating: A Guide for Project Managers" by Thomas J. Scanlon.
    • Available on various online platforms like ProjectManagement.com. This article provides a detailed explanation of top-down estimating, its applications, and advantages and disadvantages.
  • "Top-Down vs. Bottom-Up Cost Estimating: Which is Right for You?" by Lisa M. Gansky.
    • This article explores the differences between top-down and bottom-up cost estimating and helps project managers choose the appropriate method based on their project needs.
  • "Cost Estimating Techniques: An Overview" by American Society for Engineering Education.
    • This article offers a general overview of various cost estimating techniques, including top-down approaches, and highlights their key features.

Online Resources

  • Project Management Institute (PMI): www.pmi.org
    • PMI provides a wealth of resources on project management, including cost estimation. Their website offers articles, webinars, and publications on various aspects of cost estimation, including top-down approaches.
  • Cost Estimating and Analysis Society (CEAS): www.ceas.org
    • CEAS is a professional society dedicated to cost estimating and analysis. Their website provides information on best practices, standards, and resources for cost estimation, including top-down approaches.
  • University of Washington's Department of Civil and Environmental Engineering: https://depts.washington.edu/cee/courses/cee-599-cost-estimation-and-risk-analysis/
    • This page offers course materials and resources on cost estimation, including top-down methods, which can be useful for understanding the theoretical concepts and applications.

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