Introduction / Context:
Estimating moves from broad, early-stage opinions of cost to precise, tender-ready numbers. A detailed quantity survey tied to drawings and specifications yields the tightest accuracy band—used for bids, control budgets, and lender reviews. This question asks you to identify the standard name for that highest-accuracy class.
Given Data / Assumptions:
- Project has sufficiently developed design documents (drawings, specs, schedules).
- Material take-offs and installation quantities are fully measured.
- Unit rates reflect labour productivity, wage scales, equipment, and market pricing.
Concept / Approach:
Estimate classifications typically progress from Order of Magnitude/Conceptual, to Preliminary/Approximate, to Definitive (or Detailed). The definitive estimate derives from a complete bill of quantities, supplier quotations, and construction means-and-methods assumptions, producing the most accurate pre-construction cost forecast.
Step-by-Step Solution:
Establish scope completeness (drawings/specs sufficiently detailed).Perform quantity take-off for all trades; compile a priced bill of quantities.Apply current market rates, labour productivity, and equipment costs; include overheads, risk allowance, and escalation as applicable.
Verification / Alternative check:
Benchmark accuracy against historical projects—definitive estimates commonly target tighter accuracy (e.g., ±5% to ±10%) compared with conceptual (e.g., ±30% to ±50%).
Why Other Options Are Wrong:
Conceptual: used with sparse scope; accuracy is much wider.Probabilistic: describes method of handling uncertainty, not the estimate class per se.None/Screening: do not reflect a fully detailed take-off.
Common Pitfalls:
Treating a partial design as definitive; omitting indirects, preliminaries, and risk allowances that impact out-turn cost.
Final Answer:
Definitive estimate
Discussion & Comments