7.9 Opinions of Probable Cost & Value Engineering

1. Two Blueprint Tasks That Travel Together

Design Development includes both Develop Opinion of Probable Costs and Evaluate Value Engineering Alternatives. They are tested together because the second is what happens when the first is wrong, or when the budget moves.

2. Opinion of Probable Construction Cost

The profession uses the phrase "opinion of probable construction cost" rather than "estimate" for a legal reason: the landscape architect has no control over the cost of labor, materials, the contractor's methods, or competitive bidding conditions. Standard agreements state this expressly. Representing a cost opinion as a guaranteed price converts professional judgment into a warranty and voids errors-and-omissions coverage.

Methods by phase

The progression matters because a cost opinion's precision must match the information behind it. Reporting a concept-level number to the dollar implies a certainty the drawings cannot support.

Contingency and escalation — different things

• Design contingency covers scope that exists but is not yet drawn. It is highest at concept (commonly 15–20%) and decreases as the documents resolve, often to 5–10% at construction documents.
• Escalation covers price movement between the estimate date and the anticipated midpoint of construction. It is a function of time and market, not of design resolution, and on a long-phased project it can exceed the design contingency.
• Construction contingency is the owner's allowance for changes during construction and is held by the owner, not embedded in the design estimate.

Collapsing these into one "contingency" number is a common error: a project with complete documents still needs escalation if it will not bid for eighteen months.

What the opinion must include

Soft costs are regularly omitted and regularly cause the shortfall: design fees, survey and geotechnical, permits and impact fees, testing and inspection, construction administration, utility connection charges, and owner-furnished items. A "construction cost" opinion excludes these by definition, so the report must state what is in and what is out.

3. When Bids Exceed the Budget

Standard professional services agreements establish a sequence when the lowest bona fide bid exceeds a fixed limit of construction cost the owner has set. The owner may:

1. Approve the increase and award,
2. Authorize rebidding or renegotiation,
3. Terminate the project,
4. Implement other mutually acceptable action, or
5. Revise the project scope and quality as required to reduce cost.

If the owner elects the last option, the landscape architect is typically obligated to modify the documents at no additional fee. This is the exam's most-tested consequence: a fixed limit of construction cost is a meaningful contractual commitment, and accepting one without a stated contingency and escalation allowance transfers market risk onto the designer.

4. Value Engineering Is Not Cost Cutting

Value engineering (VE) is a structured methodology, originating in wartime materials substitution at General Electric, that analyzes function and seeks to deliver the required function at lower total cost. Its defining ratio:

$\text{Value} = \frac{\text{Function}}{\text{Cost}}$

Value rises when function is maintained and cost falls, or when cost is constant and function improves. Deleting function to lower cost does not raise value — it is cost cutting.

The function analysis step

The discipline of formal VE is expressing each element's function as an active verb plus a measurable noun, then asking what else could perform that function:

Expressing function this way separates the requirement from the solution and is what distinguishes VE from a line-item deletion exercise.

The standard VE job plan

1. Information — gather cost, scope, and the Basis of Design
2. Function analysis — define functions in verb-noun terms and identify high cost-to-function ratios
3. Creative — generate alternatives without evaluating them
4. Evaluation — screen alternatives against function, life-cycle cost, and schedule
5. Development — develop the surviving ideas into proposals with cost and technical backup
6. Presentation — present to the owner for decision
7. Implementation — incorporate accepted proposals and update the documents

Life-cycle cost, not first cost

A VE proposal must be evaluated on life-cycle cost: initial cost plus operations, maintenance, replacement, and disposal over the analysis period, discounted to present value. Landscape work is unusually vulnerable to false savings here:

• Reducing planting soil depth lowers first cost and raises plant replacement cost for the life of the project
• Substituting a shorter-lived paving system lowers first cost and guarantees an earlier full replacement
• Deleting irrigation from a newly installed planting saves capital and frequently costs the entire planting
• Reducing tree size at installation often has negligible long-term effect, because smaller nursery stock establishes faster and commonly overtakes larger transplanted stock — this is one of the genuinely good landscape VE moves

The landscape architect's obligation on a VE proposal

When a VE proposal would reduce performance below the Basis of Design or create a safety or code deficiency, the landscape architect must document the objection in writing. Accepting a proposal that deletes a required accessible route feature, reduces protective surfacing below the tested critical fall height, or eliminates required stormwater treatment volume is not a cost decision; it is a code and liability decision, and silence transfers responsibility to the designer.

5. Exam Traps & Pitfalls

1. Calling a cost opinion an estimate or a guarantee. The designer controls neither market nor bidding conditions.
2. Merging design contingency and escalation. One tracks drawing resolution; the other tracks time and market.
3. Presenting concept-level costs to the dollar. Precision must match the information behind it.
4. Calling scope deletion value engineering. VE preserves function; deleting function is cost cutting.
5. Evaluating VE on first cost. Life-cycle cost governs, especially for soil, planting, and paving.
6. Accepting a VE proposal that breaches code. Object in writing; a safety or accessibility deficiency is not a cost trade.