Glossary - Construction Project Scheduling and Control - page 484

submit their payment requests to the general contractor, who combines them
with his or her own in one total payment request to the owner. Typically, this
process is done on a monthly basis.
Percent Complete —See Activity Percent Complete or Project Percent Complete .
Pessimistic Duration —The duration under almost the worst case scenario within
the realistic—even though it may not be likely—realm of expectations.
Planned Value (PV) —See Budgeted Cost for Work Scheduled (BCWS) .
Portfolio —A group of projects, not necessarily related or dependent, usually under
one project manager or department. The PMI defines it as a collection of
projects or programs, and other work that are grouped together to facilitate
effective management of that work to meet strategic business objectives.
Precedence Diagramming Method (PDM) —A node network (see Activity on
Node Network) that allows for the use of four types of relationships: finish-to-
start (FS), start-to-start (SS), finish-to-finish (FF), and start-to-finish (SF).
Precedence Network —See Precedence Diagramming Method .
Predecessor Activity —An activity that has to finish (or start) in order for the
succeeding activity or activities to start (or finish). It also has been defined as an
activity that has some measurable portion of its duration logically restraining a
subsequent activity or activities. 1
Probability Density Function (PDF) —A function used to compute probabilities
for a continuous random variable at a certain value. The area under the curve of
a probability density function over an interval represents probability (chance of
occurrence): f (x)=Pr ( X = x ).
Probability Distribution —A function or mathematical model that describes all of
the values that the random variable can take and the probability (chance of
occurrence) associated with each. Also called a probability function .
Probability Universe —The set of values of all possible outcomes for a random
variable.
Procurement —The process of acquiring materials, equipment, and/or services from
external sources for use in a project. It is a process that usually starts long before
the start of the construction process and ends with project completion or project
closeout.
Professional Engineer (PE) —An engineer licensed by an authority (usually the
government of the state) after fulfilling certain requirements (minimum
experience and passing an exam).
Pro Forma —A projection or estimate of the cost/benefit ratio or rate of return on
an investment. Project owners and investors usually use a pro forma to help
them make a decision about whether or not to carry out the project. Typically,
a pro forma includes all expected costs (initial, recurring, and occasional) and
expected revenues throughout the life cycle of the project, and then calculates
the rate of return.
1 Theoretically, this portion can be zero, but practically it has to be greater than zero.