Standard Project Estimating

*Standard Project Estimating*
*Estimating Method*	*Generic Type*	*WBS Relationship*	*Accuracy*	*Time to prepare*
Parametric	Rough Order of Magnitude (ROM)	Top Down	-25% to +75%	Days
Analogy	Budget	Top Down	-10% to +25%	Weeks
Engineering (grass roots)	Definitive	Bottom up	-5% to +10%	Months