Topic 2 - Project Cost Estimating Flashcards
When do we do cost estimating?
Concept - estimate
Design - estimate
Bidding - estimate
Construction - estimate
Less effort/ low accuracy —-> more effort, more accuracy
Why do we do cost estimating?
Financing and budgeting for owner and contractor.
What is a conceptual estimate?
2 types?
- completed prior to design
- used by owner to determine feasibility of project and magnitude of scope(whether to proceed with project or not)
- low accuracy
- low effort
- Analogous estimating: “top-down” estimate based on previous projects: Cost per function, unit area, or unit volume methods
- Parametric estimating: statistical relationship between historical data and project variables/characteristics
What is a preliminary estimate?
- complated at +/- 40% of design stage
- used to determine if company should proceed with project or not
- can be used to evaluate alternate options
- based on unit costs of similar cost elements from previous projects
What is an engineers estimate? aka owners estimate
- COMPLETED AFTER DETAILED DESIGN IS FINISHED
- used to conduct a final feasibility check
- used to provide a reliable reference point for bids
- can be used to secure resources (financing_
- based on a detailed costing of each element of work in work breakdown structure (WBS)
What is a bid estimate/detailed estimate? -aka contractors estimate
- most accurate
- based on complete bid documents
- “bottom up” estimating: detailed, first principles, based on lowest elements in WBS; includes detailed assessment of risks and opportunities and desired profit margin/markup
Conceptual Estimate types?
- Analogous estimating: “top-down” estimate based on previous projects: Cost per function, unit area, or unit volume methods
- Parametric estimating: statistical relationship between historical data and project variables/characteristics
Bid estimate/detailed estimate type?
-“bottom up” estimating: detailed, first principles, based on lowest elements in WBS; includes detailed assessment of risks and opportunities and desired profit margin/markup
Classes of estimates
Class 1 to class 5
- class 5 has very little maturity level (% of project completed), so will be most unnacurate and low preparation effort
- class 1 has high maturity level (65%to100%), so has very high accuracy and high preparation effort
Estimate class for bid/tender?
Estimate for feasibility?
Estimate for budget budget authorization/control?
- class 4 or 5
- class 1 or 2
- class 3
Methodology for class 4/5 estimates?
Methodology with class 3
Methodology with class 1/2
4/5: detailed unit cost with forced detailed take-off
3: semi detailed unit costs
1: capacity factored
2: equipment factored
Competitive bidding/tendering: who is it conducted by?What is a tender? purpose of competitive bidding?
- conducted by client (owner) or its consultant
- a tender is a bid, a formal offer to do work based upon certain terms
- purpose is to provide competition and thereby reduce costs to owners
5 methods of bidding?
-open competitive
-prequalified
-invited
negotiated
-joint ventures - one time
Steps in competitive bidding?
1) owner issues request for bids (letter of invitation, advertisement, request for pre-qualification, …)
2) contractor views/obtains tender documents
3) contractor makes decision to bod or not to bid
4) Contractor prepares estimate and tender submission
5) contractor submits bid
6) owner opens bids and awards contract
- public bid opening and closed bid opening
Types of bid openings?
Public bid opening:
- public sector owners (government, schools, hospitals)
- basis for award: generally lowest price of prequalified
Closed bid opening:
- private sector (non govt owners)
- basis for award: not necessarily lowest price (experience, capability, realistic bid, quality of subcontractors and suppliers)