Duration Analogous Estimating: Definition, Exam Tips, and Traps
PMBOK v8 Definition
Analogous estimating is a technique for estimating the duration, cost, or required resources for an activity or a project using historical data from a similar activity or project. When estimating durations, this technique relies on the actual duration of previous, similar projects as the basis for estimating the duration of the current project. It is a gross value estimating approach, sometimes adjusted for known differences in project complexity.
Why It Matters for the Exam
Analogous duration estimating appears frequently on the PMI exam, especially in questions testing your ability to select the appropriate estimating technique under specific project conditions. You will encounter it in situational questions where limited detailed information is available, and the project manager must choose a cost-effective and time-efficient estimation method.
Key Points to Remember (for the exam)
- Definition: Uses actual duration from previous, similar projects as the basis for estimating current project duration
- Nature: A gross value estimating approach (not detailed, top-down)
- Adjustment: Sometimes adjusted for known differences in project complexity
- Best Used When: Limited detailed information about the project is available
- Cost and Time: Generally less costly and less time-consuming than other techniques
- Accuracy Trade-off: Can be less accurate than other estimating methods
- Application Scope: Can be applied to a total project or to segments of a project
- Combination: May be used in conjunction with other estimating methods
- Parameters Used: Duration, budget, size, weight, and complexity from previous similar projects
Typical PMI Exam Example
A project manager is assigned to a new software development project. The organization has completed three similar projects in the past two years. The current project has a vague scope definition, and the sponsor needs a quick duration estimate within two days. Which estimating technique should the project manager use?
Answer: Analogous estimating, because it relies on actual duration from previous similar projects and is less time-consuming than other techniques when detailed information is limited.
PMI Exam Traps
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Trap: Confusing analogous estimating with parametric estimating
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Reality: Analogous uses historical data from a similar project as a gross value; parametric uses statistical relationship between variables (e.g., square feet per hour)
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Trap: Thinking analogous estimating is always the most accurate method
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Reality: Analogous estimating can be less accurate than other techniques; accuracy depends on similarity between projects
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Trap: Believing analogous estimating requires detailed project information
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Reality: Analogous estimating is specifically used when there is limited detailed information about the project
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Trap: Assuming analogous estimating only applies to the total project
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Reality: Analogous duration estimates can be applied to a total project or to segments of a project
Important PMI Connections
| Related Concept | Relationship Type | Exam Attention Point |
|---|---|---|
| Parametric Estimating | Alternative technique | Tested on when to use each; parametric uses statistical relationships, analogous uses historical similarity |
| Three-Point Estimating | Complementary technique | Analogous may be used alongside three-point for ranges; analogous provides baseline, three-point adds uncertainty |
| Bottom-Up Estimating | Opposite approach | Analogous is top-down (gross value), bottom-up is detailed per activity; tested on which to use based on information availability |
| Project Scope (Scope Performance Domain) | Input relationship | Scope information quality determines if analogous estimating is appropriate; limited scope = analogous preferred |
Quick Review Questions
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When should a project manager choose analogous duration estimating over parametric estimating?
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What are the main advantages and disadvantages of using analogous estimating for project duration?
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Can analogous duration estimates be applied to only a portion of a project, or must they always cover the entire project?
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What types of parameters from previous projects can be used as the basis for analogous estimating?
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Under what project conditions is analogous estimating most appropriate to use?
PMBOK v8 Reference
Section 2.4 - Planning Performance Domain (Estimating Effort and Duration)