## What is Analogous Estimating?

The dictionary meaning of “**Analogous**” is “**similar or comparable**“. This meaning says it all.

In simple words, with Analogous Estimating we estimate X, based on the estimates of Y, provided both X and Y are similar or comparable.

Analogous Estimating is also called **Top-Down Estimating.
**

## PMBOK Definition of Analogous Estimating

**PMBOK defines** Analogous estimating as *“a technique for estimating duration or cost of an activity or a project using historical data from a similar activity or a project.”*

Here, the point, using **Historical data is the key. **

Analogous estimating uses parameters from previous similar projects such as duration, budget, weight, size, complexity etc as a basis for estimating the same parameter or measure of the project in question.

## Analogous Estimating Example

**Example: Estimate the amount of duration and cost for building a bridge over a river.**

In Analogous estimating we check the Organizational Process Assets (OPA) for any comparable projects that were executed in the past. Suppose we found that a bridge was built on the same river at some other place. Now use your expert judgement and find the approximate duration and cost for building the bridge in question.

So the key point to remember is, **In Analogous estimating, you first look for a similar project in the past, get its data, and use your expert judgement to find the approximate duration or cost for your project.**

The **accuracy** of analogous estimation **depends** **on** the degree of **similarity** between your current project and the project you are comparing it with.

**Analogous Estimating – Important Points to Remember**

- Analogous Estimating can be used to estimate
**both Duration and cost.** - It makes use of
**historical data**of a similar project to estimate the current project. - It is the
**Fastest technique**to calculate estimates, however, less accurate. - Analogous Estimating is also called
**Top-Down Estimating.** - It is Used in estimating when you
**don’t have detailed information**about the project in question. - Analogous Estimating is
**Less Accurate, Less Time consuming, and Less Costly.** - Analogous Estimating can be done for the
**entire project or only for part**of a project. - Analogous Estimating
**can be****used along with other estimating methods.**

Other commonly used estimating techniques are –

Also check the comparison of the Estimating Techniques.