Tender Evaluation Red Flags: Why Lowest Price Can Cost More

The cheapest tender is not always the best tender.

In construction, a low tender can be a genuine saving. It can also be a warning sign that something has been missed, qualified, underpriced, or pushed into a future claim. The challenge is to understand the difference before the contract is awarded.

A good tender evaluation does not simply ask, "Who is cheapest?" It asks, "Are all tenderers pricing the same scope on the same commercial basis?"

That is where Quantity Surveying review becomes important.

Red flag 1: Exclusions that remove real scope

Exclusions are one of the most important items to check. A contractor may submit a low price but exclude work shown in the drawings, specifications, BQ, or tender requirements.

Common exclusions may include:

disposal of debris
temporary protection
testing and commissioning
authority submissions or fees
scaffolding or access equipment
making good after hacking or installation
attendance for nominated subcontractors
overtime or restricted working-hour requirements

An exclusion is not automatically wrong. Sometimes a tenderer is simply clarifying a scope boundary. The problem arises when the excluded item is actually required for the project but has not been allowed for in the tender comparison.

Before recommending award, the project team should decide whether the exclusion needs to be withdrawn, priced separately, or added back into the tender comparison.

Red flag 2: Qualifications that change the tender basis

Qualifications are tender conditions or assumptions added by the contractor. They may affect payment terms, programme obligations, risk allocation, materials, warranties, validity periods, or variation valuation.

Examples include:

price valid for only a short period
payment required before delivery
programme subject to material availability
alternative material proposed without full comparison
variation rates to be agreed later
price subject to fluctuation
selected contract clauses not accepted

Qualifications can change the commercial basis of the tender. A tender may look cheaper because it has shifted risk back to the client.

The QS should identify these qualifications clearly so the client understands what is being accepted.

Red flag 3: Provisional sums that are too low

Provisional sums are useful when some work cannot be fully defined at tender stage. However, unrealistic provisional sums can make a tender look lower than it really is.

For example, a contractor may include a very small allowance for an item that is likely to cost much more. If the item is later instructed at a higher actual cost, the final contract cost may increase.

Tender evaluation should check whether provisional sums are reasonable for the likely scope. If not, the tender comparison may need to be adjusted.

Red flag 4: Unrealistic rates for items likely to change

Some rates matter more than others. If an item is likely to vary during construction, an unrealistic rate can affect the final account.

For example:

excavation rates may matter if ground conditions change
wall or floor finish rates may matter if quantities increase
hacking and making-good rates may matter in renovation work
preliminaries may matter if the programme is extended

A very low rate may appear attractive during tender, but it may cause disputes later if the contractor argues that the rate does not reflect the changed work. A very high rate may also create risk if the item quantity increases.

The QS should review key rates, not just totals.

Red flag 5: Missing preliminaries and attendance costs

Preliminaries are sometimes underpriced because they do not look like direct construction work. However, they are essential to project delivery.

They may include:

site supervision
temporary facilities
insurances
safety requirements
protection
setting out
access arrangements
coordination
testing support
cleaning and handover requirements

If preliminaries are unrealistically low, the contractor may try to recover cost later through claims, variations, or reduced site support.

For the client, this can affect both cost and project administration.

Red flag 6: Alternative materials without clear comparison

Alternative materials or methods can be useful if they reduce cost without reducing performance. But they must be reviewed properly.

Tender evaluation should check:

whether the alternative meets the specification
whether quality, warranty, durability, and maintenance are affected
whether approval is required from consultants, authorities, or the client
whether the alternative affects programme or coordination
whether the tender price is based on the original specification or the alternative

If an alternative is accepted without clear review, the project may face quality, approval, or performance issues later.

Red flag 7: Large price gaps without explanation

Large price gaps between tenderers should be investigated. The gap may be due to genuine efficiency, market strategy, or better procurement. It may also indicate missing scope or misunderstanding.

A tender that is much lower than the others should not be rejected automatically. But it should be checked carefully.

Questions to ask include:

Did the contractor price the latest tender documents?
Are all BQ items priced?
Are there exclusions or qualifications?
Are key rates realistic?
Are provisional sums and allowances adequate?
Does the contractor understand the programme and site constraints?

If the tenderer cannot explain the gap clearly, the risk remains with the client.

How the QS normalises tenders

Tender normalisation is the process of adjusting tenders so they can be compared more fairly. It may include:

adding back exclusions
adjusting provisional sums
comparing key rates
clarifying missing prices
reviewing qualifications
checking arithmetic
preparing a commercial comparison
listing tender queries for interview

The purpose is not to force every tender to become identical. The purpose is to help the client understand the real commercial position behind each offer.

Questions to ask before award

Before recommending a contractor, the project team should be able to answer:

What is included in the tender price?
What is excluded?
What assumptions has the contractor made?
Are the key rates reasonable?
Are provisional sums realistic?
Are there any qualifications affecting contract risk?
Is the programme achievable?
How will variations be valued?
Is the tender technically aligned with the project requirements?

A clear recommendation should explain both price and risk.

Final thought

The lowest tender is not always the lowest final cost. A tender that is incomplete, heavily qualified, or based on unrealistic allowances can become more expensive after award.

A good tender evaluation helps the client see beyond the headline number. It identifies which tender is commercially clear, technically aligned, and less likely to create avoidable disputes during construction.

TYH Quantity Surveying Consultant supports tender documentation, BQ preparation, tender analysis, cost planning, contract administration, claims review, and final account matters. If you need support reviewing tender submissions, contact TYH to discuss your project.