# What is an order of magnitude budget?

What is an order of magnitude budget? The short answer is: Rough order of magnitude (ROM) refers to an initial estimate of the cost of a project or parts of a project. It has an

## What is an order of magnitude budget?

The short answer is: Rough order of magnitude (ROM) refers to an initial estimate of the cost of a project or parts of a project. It has an expected accuracy of -25% to +75% according to the PMBOK (other sources suggest -50% to +50%).

What is the order of magnitude estimation?

An order-of-magnitude estimate of a variable, whose precise value is unknown, is an estimate rounded to the nearest power of ten. For example, an order-of-magnitude estimate for a variable between about 3 billion and 30 billion (such as the human population of the Earth) is 10 billion.

What does ROM in construction mean?

Rough order of Magnitude
Rough order of Magnitude (ROM) Cost A ROM Cost is a general approximation of the cost of providing a stated service. It is based on experience, costs of similar services, or on a cursory examination of other vendor’s rates.

### What is the range of a rough order of magnitude estimate?

A Guide to the Project Management Body of Knowledge (PMBOK® Guide) provides the following guidelines: Rough Order of Magnitude Estimate: -25 percent to +75 percent. Budget Estimate: -10 percent to +25 percent. Definitive Estimate: -5 percent to +10 percent.

What is another name for rough order of magnitude estimate?

ROM estimate
A Rough Order of Magnitude Estimate (ROM estimate) is an estimation of a project’s level of effort and cost to complete. A ROM estimate takes place very early in a project’s life cycle — during the project selection and approval period and prior to project initiation in most cases.

What is a rough estimate?

A Rough Cost Estimate is an initial estimate that uses prior experience and other non-project data to estimate the cost of a project. It is also called a Rough Order of Magnitude (ROM) estimate, or a Conceptual Estimate. Usually it is not yet funded, and the primary parts of the project are not designed.

#### Can an order of magnitude be negative?

For example, 9.9×102 is much closer to 103 than to 102 , so we say that the order of magnitude is 3 . By the same argument, 9.9×10−3 is closer to 10−2 than to 10−3 , so we say that the order is −3 . In another meaning, it is a difference of 1 unit in the exponent of 10 in the value of a quantity.