Duration Analogous Estimating: Historical Data for Project Duration

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. This technique uses parameters from a previous, similar project, such as duration, budget, size, weight, and complexity, as the basis for estimating the same parameter or measure for a future 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.

Why It Matters for the Exam

Analogous estimating appears frequently in PMI exam questions testing your ability to select the appropriate estimation technique under specific project conditions. You will encounter this concept in questions about the Schedule Management and Cost Management knowledge areas, particularly when the scenario describes limited detailed information, early project phases, or situations requiring quick, cost-effective estimates.

Key Points to Remember (for the exam)

• Definition: Analogous estimating uses historical data from a similar activity or project to estimate duration, cost, or resources

• Parameters Used: Previous project parameters include duration, budget, size, weight, and complexity

• Key Characteristics: It is a gross value estimating approach, sometimes adjusted for known differences in project complexity

• When to Use: Frequently used when there is limited detailed information about the project

• Advantages: Generally less costly and less time-consuming than other techniques

• Disadvantage: Can also be less accurate than other estimating methods

• Application Scope: Can be applied to a total project or to segments of a project and may be used in conjunction with other estimating methods

Typical PMI Exam Example

A project manager is assigned to a new software development project during the initiation phase. The organization has completed three similar projects in the past two years. The project manager has only high-level requirements and no detailed specifications. Which estimating technique should the project manager use to quickly provide a duration estimate? Answer: Analogous estimating, because it uses historical data from similar projects and requires limited detailed information.

PMI Exam Traps

• Trap: Confusing analogous estimating with parametric estimating

• Reality: Analogous uses historical data from similar projects (gross value); parametric uses statistical relationships between variables (e.g., square footage × labor hours per unit)

• Trap: Thinking analogous estimating is always the most accurate technique

• Reality: Analogous estimating is less accurate than other techniques but is less costly and less time-consuming

• Trap: Believing analogous estimating can only be applied to the entire project

• Reality: Analogous estimates can be applied to a total project or to segments of a project

• Trap: Assuming analogous estimating requires detailed project information

• Reality: This technique is frequently used when there is limited detailed information about the project

Important PMI Connections

Quick Review Questions

1. What are the five parameters from previous projects that analogous estimating uses as the basis for estimation?

2. When is analogous estimating most appropriately used for duration estimation?

3. What are the two main advantages and the one main disadvantage of analogous estimating compared to other techniques?

4. Can analogous estimating be applied to only part of a project, or must it always be used for the entire project?

5. What distinguishes analogous estimating from parametric estimating in terms of how the estimate is calculated?

PMBOK v8 Reference

Section 2.5.2.3 - Schedule Performance Domain (Estimating Effort and Duration)