Construction estimating — which item is NOT an estimate type? Identify the option that is not a recognized category of construction cost estimate.

Introduction / Context:
Construction projects pass through estimate classes that become more accurate as design matures: from order-of-magnitude and conceptual budgets to semi-detailed and finally definite/detailed estimates. Knowing these categories helps stakeholders set contingencies and make go/no-go decisions.

Given Data / Assumptions:

• We compare listed items against standard estimate types used in practice.
• Terminology may vary slightly by organization, but the concepts are consistent.
• Accuracy improves and contingency reduces as estimates progress through stages.

Concept / Approach:
Common categories include order-of-magnitude (screening), conceptual/preliminary (budget), semi-detailed, and definite/detailed estimates. Each occurs at increasing design completeness (e.g., 0–2%, 5–15%, 20–40%, 50–100%).

Step-by-Step Solution:
Check “Initial feasibility estimate”: valid (screening or order-of-magnitude).Check “Conceptual preliminary budget”: valid (budget-level estimate during early design).Check “Definite estimate”: valid (detailed estimate near final design).Thus, none of the listed items is “not an estimate type”, so choose “None of these”.

Verification / Alternative check:
Project controls guides and cost engineering references (AACE-style classes) map closely to these categories, confirming their legitimacy.

Why Other Options Are Wrong:
Each labeled estimate corresponds to a real stage; therefore options a, b, and c are not correct as the “not an estimate”.

Common Pitfalls:

• Confusing naming conventions with concept; labels differ, but stages are universal.
• Using detailed estimates too early, which falsely implies accuracy and reduces needed contingency.

Final Answer:
None of these