ARLINGTON, Mass., Feb. 10, 2017 /PRNewswire/ -- Do you need to estimate your project? Author Johanna Rothman says, "Different kinds of estimation work for different audiences at different times."

Estimating technical work is difficult. What do you do when someone asks you for an estimate? You have other options than to blindly create a SWAG (Scientific Wild-Tush Guess.)

1. Know who and what your estimate is for.

You might only need to create an order-of-magnitude estimate for your project, so your management understands if this is larger than a space station or smaller than a breadbox—or something in between. "Your management might not need a commitment, but an idea of when you can deliver value. That's a different estimate than a detailed project estimate," says Rothman.

2. Consider a project pyramid, not a triangle.

If your management does want a detailed estimate, consider thinking about your project as a system, a pyramid, not a triangle. Project estimates depend on the organization: What the organization wants to pay for the project, the people on the project and their capabilities, and the project environment. In addition, the project estimate depends on the feature set, the acceptable defect levels and the desired release date. "If you understand your project system, you can create a reasonable estimate, especially if you use confidence ranges or three-point estimation, or some other approach that includes your uncertainty," Rothman says.

3. Know when it's worth your time to re-estimate.

Estimates expire. Once everyone understands that, it's easier to recognize when it's time to re-estimate. "When the project changes, which can include the requirements, the people, the environment or anything else, your estimate expires. That's a great time to re-estimate and replan the project," says Rothman.

Rothman's book, Predicting the Unpredictable: Pragmatic Approaches to Estimating Project Cost or Schedule is available in print and audio. It helps project teams estimate well and explain to their managers what their estimate means.

About Predicting the Unpredictable: Pragmatic Approaches to Estimating Project Cost or Schedule: You might not be able to develop an estimate at the beginning of a project that is good until the end. Few project teams can. Instead, learn a number of ways to see your project and how to address your uncertainties in ways your managers will accept.

For more information, see http://www.jrothman.com/books/predicting-the-unpredictable-pragmatic-approaches-to-estimating-cost-or-schedule/

About Johanna Rothman:

Johanna Rothman, known as the Pragmatic Manager, http://www.jrothman.com/pragmaticmanager/, provides frank advice to the tough problems of managing projects, people and risk. She is the author of several books, http://www.jrothman.com/books/.