What type of estimate uses a mathematical relationship between variables to forecast duration?

What type of estimate uses a mathematical relationship between variables to forecast duration?

• A. Analogous Estimate
• B. Bottom-Up Estimate
• C. Parametric Estimate
• D. Three-Point Estimate

Answer: (C)

Parametric estimation uses a mathematical relationship between variables to forecast duration. By deriving a model from historical data—such as days per function point, hours per story point, or days per unit of size—you can multiply the project size by a rate to estimate total time. This method scales with the work amount and can be applied early in a project when details are limited, as long as the chosen relationship fits the data well. It relies on consistent, measurable factors and a known productivity pattern, so accuracy hinges on good historical data and an appropriate model.

Parametric estimation uses a mathematical relationship between variables to forecast duration. By deriving a model from historical data—such as days per function point, hours per story point, or days per unit of size—you can multiply the project size by a rate to estimate total time. This method scales with the work amount and can be applied early in a project when details are limited, as long as the chosen relationship fits the data well. It relies on consistent, measurable factors and a known productivity pattern, so accuracy hinges on good historical data and an appropriate model.