PMP Certification: 4 Estimating Techniques for Project Managers

By Cynthia Snyder Stackpole

Part of PMP Certification All-In-One For Dummies Cheat Sheet

You can apply PMP (project management professional) estimating techniques to resources, effort, duration, and costs. PMPs use different methods of estimating, depending on the situation.

Estimating method Description
Analogous estimating Generally used at the start of the project when not much is
known. Compares the current project with past similar projects. A
quick and relatively easy method of estimating, although not
terribly accurate.
Parametric estimating Used for estimates that are quantitatively based, such as
dollars per square foot or number of installations per day. A
relatively simple method, but not every activity or cost can be
estimated quantitatively.
Three-point estimating Accounts for uncertainty associated with estimating by
determining an optimistic (best case, represented by O), most
likely (represented by M), and pessimistic (worst case, represented
by P) scenario. The most likely estimate is weighted most
heavily.

The equation is
(O + 4M + P) / 6

Bottom-up estimating Used when there is significant detail about the activity. A
detailed assessment of the resources, capabilities, and amounts are
used to determine an accurate duration or cost estimate. This is
the most accurate method but also the most time-consuming and
expensive form of estimating.