Analogous estimating is a technique used in project management to estimate the duration or cost of an activity or project based on historical data from similar activities or projects. It is often utilized in the early stages of project planning when limited detailed information is available. By ref…Analogous estimating is a technique used in project management to estimate the duration or cost of an activity or project based on historical data from similar activities or projects. It is often utilized in the early stages of project planning when limited detailed information is available. By referencing previous projects that are comparable in size, complexity, scope, and other relevant factors, project managers can derive estimates for the current project's activities.
This method relies heavily on expert judgment and the experience of those involved in the estimation process. The accuracy of analogous estimates depends on the degree of similarity between the past and current projects and the expertise of the estimators in identifying and adjusting for differences. Analogous estimating is considered a top-down approach, as it starts with the overall characteristics of past projects to estimate the current one.
One of the advantages of analogous estimating is its relative speed and simplicity. It requires less time and resource investment compared to more detailed estimation techniques, making it suitable for initial planning phases or when quick approximations are necessary. However, it may be less accurate than other methods because it doesn't account for the detailed nuances of the specific activities being estimated.
To enhance the accuracy of analogous estimates, project managers should carefully select historical data from projects that are closely aligned with the current project in key aspects. Adjustments may be necessary to account for differences in technology, team experience, market conditions, or other variables that could impact activity durations. Analogous estimating can also be combined with other estimation techniques to improve reliability.
In summary, analogous estimating is a practical technique for estimating activity durations by leveraging historical data from similar projects. Its effectiveness depends on the quality of the data used and the judgment applied in adjusting for differences. It serves as a useful tool for project managers when detailed information is lacking or when quick estimates are needed, but it should be used with caution due to its potential for lower accuracy.
Analogous Estimating in Project Management
What is Analogous Estimating?
Analogous estimating is a technique used in project management to estimate the duration, cost, or size of a project by comparing it to similar past projects. It's considered a top-down estimation technique that uses historical data from previous similar projects as the basis for estimating the current project.
Why is Analogous Estimating Important?
Analogous estimating is important because it:
- Provides quick estimates when detailed information is limited - Requires minimal time and resources to develop - Works well in early project stages when scope details are still emerging - Leverages organizational knowledge and experience - Helps validate estimates created using other methods - Creates a starting point that can be refined as more information becomes available
How Analogous Estimating Works
1. Identify similar past projects: Find completed projects with similarities to your current project
2. Determine relevant parameters: Choose which characteristics are most important for comparison (size, complexity, team skills, etc.)
3. Assess the degree of similarity: Evaluate how closely the past projects match your current project
4. Apply expert judgment: Use subject matter expertise to adjust the historical data based on differences
5. Create the estimate: Use the historical data with appropriate scaling factors to produce your estimate
Key Considerations:
- Accuracy level: Generally less accurate than other methods (typical accuracy range: -25% to +75%) - Scaling factors: May need to adjust for size, complexity, or technology differences - Expert judgment: Relies heavily on expertise to identify relevant past projects - Documentation: Document assumptions and reasoning behind your analogies
Exam Tips: Answering Questions on Analogous Estimating
1. Recognize when to use it: - Early project phases - Limited detailed information available - Need for quick estimates - Previous similar projects exist
2. Know its strengths: - Speed and low cost - Simplicity - Leverages historical knowledge - Useful for high-level planning
3. Understand its limitations: - Less accurate than parametric or bottom-up methods - Highly dependent on truly comparable projects - Subject to personal bias - May overlook project-specific elements
4. Remember it's considered a form of expert judgment: - Based on experience and historical data - Requires subject matter expertise
5. Distinguish from other estimation techniques: - Parametric estimating: Uses statistical relationships and parameters - Three-point estimating: Uses optimistic, most likely, and pessimistic scenarios - Bottom-up estimating: Estimates each work package in detail and sums them up
6. Understand its typical accuracy range: - Less precise than detailed methods - PMI recognizes it as having broader variance than other techniques
7. Be aware of when analogous estimates get refined: - As more project details become available - At key decision points in the project - When moving from high-level to detailed planning
In exam scenarios, look for situations where rapid estimates are needed with limited information, or where the question mentions comparing to similar past projects. This often indicates analogous estimating is the appropriate technique.