Parametric Estimating Guide
Parametric Estimating is an essential technique in project management, especially in cost and time management.
Importance: This technique is important because it provides a quick, accurate, and easily verifiable method of estimating cost, time, or resource requirements for a project. The technique depends on the relationship between variables, thus providing more accurate estimates as more data becomes available.
Definition: Parametric Estimating is a quantitative method of estimating where you use statistical data about previous similar projects as the basis for estimating the same parameter or measure for a future project. It leverages historical data and mathematical equations to calculate estimates.
How it works: In parametric estimating, a unit or parameter is identified, then a per-unit cost or time is assigned. By multiplying the known elements by the per-unit cost or time, you can estimate the total cost or duration.
Exam Tips: Questions on parametric estimating in the exam will more than likely focus on your understanding of how the technique works. Many questions will present a scenario requiring you to apply the technique. Be sure to know how to estimate project costs or duration correctly using parametric estimating. Remember, if you are given a scenario where there is a lot of historical data available and you need to calculate a cost or time estimate, parametric estimating is likely the best technique to apply.
Another common mistake is confusing parametric estimating with analogous estimating. Parametric estimating uses mathematical models and typically involves a statistical relationship, whereas analogous estimating is more of a 'guesstimate' based on past experiences.
Answering Questions on Parametric Estimating: To answer questions regarding Parametric Estimating, it's essential you understand its process - identifying the parameter, assigning unit cost/time, and then calculating the total. Always make sure to scrutinize the given data before choosing your approach.
Remember, Parametric Estimating is most suitable when there's ample historical data. So, maintain your calm and let the data guide your answers. Always double-check your calculations and ensure you've applied the correct units throughout. Keep an eye out for 'trap' questions that may want to confuse Parametric with Analogous or Bottom-up Estimating.