The difference between a variant and an option
It is structural and often confused.
The option is provided for by the package. The client has asked for a price for an alternative or additional work, and every contractor prices it.
The variant is proposed by the contractor. It substitutes a different solution for the one described, on its own initiative.
The option preserves comparability, since every bid carries it.
The variant breaks it, since only one contractor proposes it and it does not cover the same work.
This difference governs the treatment: the option is analysed; the variant must first be classified.
| Notion | What it changes | Treatment in analysis |
|---|---|---|
| Variant | The technical solution proposed | Compared with the base solution |
| Option | Work added or removed | Priced separately |
The condition for a variant to be admissible
A single but absolute requirement.
A variant can only be analysed if it is accompanied by the price of the base solution.
Without that, the bid cannot be compared with the others, and the variant becomes a means of escaping comparison rather than a proposal for improvement.
This requirement must appear in the tender documents, failing which it will not be observed.
In public contracts, the admissibility of variants is governed by the applicable rules, and whether they are admissible depends on what the package provided for.
In private contracts, everything depends on what the client wrote, in line with the principle set out in the article on public and private contracts.
What variants really add
Three possible contributions, and one risk. Variants can improve the solution but complicate comparison.
A saving, where the contractor knows an equivalent solution that costs less.
A technical improvement, where it proposes a more durable or better-performing solution.
A gain in time, where the solution proposed is quicker to build.
The risk is the transfer of responsibility. A variant accepted commits the client to a solution it did not design, and whose implications the design team has not necessarily verified in full.
Accepting a variant therefore requires it to be validated technically, not merely priced.
How to handle them in analysis
Four stages.
First compare the base bids with each other, setting the variants aside for the moment.
Then classify each variant, technically and not only economically.
Price the difference, including indirect consequences for other packages.
Decide expressly, documenting the reason for acceptance or refusal.
The order matters: analysing variants before base bids leads to comparing different things and choosing on an impression.
The case of variants driven by circumstances
A particular and frequent situation.
A contractor may flag that a solution described is unbuildable or unsuitable.
That information is valuable and must be treated as such, even when it arrives in the form of a variant.
It often reveals a design defect, and treating it as a mere commercial proposal loses the information.
The right response is to verify the objection technically, then, if well founded, to correct the package for every contractor.
What this means for a professional
Four rules.
Provide in the package for the regime applying to variants, admitted or not, and on what conditions.
Require the price of the base solution to accompany any variant.
Compare base bids before variants, without exception.
Have any variant adopted validated technically, design responsibility not transferring through price.
This article sets out a method of professional orientation. It does not constitute legal advice.