Which estimating technique uses a mathematical relationship between variables to estimate duration based on a parameter such as cable count?

Which estimating technique uses a mathematical relationship between variables to estimate duration based on a parameter such as cable count?

• A. Analogous Estimation
• B. Parametric Estimate
• C. Bottom-Up Estimation
• D. Expert Judgment

Answer: (B)

Parametric estimation uses a mathematical relationship between variables to estimate duration from a parameter such as cable count. By building a model from historical data, you predict total time by applying a unit rate or a functional formula to the parameter (for example, duration per unit of cable times the total cable count). This approach is efficient and scalable when there’s a clear, quantifiable link between the parameter and the work, and it often sits between quick analogies and detailed bottom-up work in precision. Analogous estimation relies on comparing to a past project without a formal equation, bottom-up builds estimates from detailed task-level work, and expert judgment depends on experienced opinion without a model. Parametric estimation stands out because it explicitly ties duration to a measurable parameter through a mathematical relationship.

Parametric estimation uses a mathematical relationship between variables to estimate duration from a parameter such as cable count. By building a model from historical data, you predict total time by applying a unit rate or a functional formula to the parameter (for example, duration per unit of cable times the total cable count). This approach is efficient and scalable when there’s a clear, quantifiable link between the parameter and the work, and it often sits between quick analogies and detailed bottom-up work in precision.

Analogous estimation relies on comparing to a past project without a formal equation, bottom-up builds estimates from detailed task-level work, and expert judgment depends on experienced opinion without a model. Parametric estimation stands out because it explicitly ties duration to a measurable parameter through a mathematical relationship.