Request for proposal: buying an approach when the solution is open

Where a proposal round is the right instrument

Use it when the requirement can be stated as an outcome and more than one credible route exists to reach it. Equipment and line projects, transfers of scope to a contract manufacturer, redesign-and-supply packages, and multi-part programmes where the supplier will propose its own process split all qualify. It is the wrong instrument for a defined part on a released drawing, where a proposal round simply adds pages to a price enquiry. The test is whether you would learn something from reading how a supplier intends to do the work.

Writing the requirement as an outcome, with the constraints named

Describe what the delivered capability must achieve: the output rate, the part families it must handle, the quality performance expected, the interfaces with existing equipment and systems, the site constraints, the utilities available, the acceptance criteria and who runs it afterwards. Name the constraints that are genuinely fixed and say which are preferences. Suppliers waste effort designing around assumed constraints that were never real, and they also propose elegant solutions that cannot be installed because a ceiling height or a floor loading was never mentioned. Include how the finished capability will be accepted and by whom, since acceptance criteria discovered late become the most contested part of a project.

Scoring method before proposals arrive

Agree the evaluation criteria and their relative weight before anything is received, and involve the people who will operate the result. Without that discipline, evaluation drifts toward whichever proposal is best presented, or collapses into price once the technical discussion becomes uncomfortable. Criteria that earn their place: technical soundness of the approach, relevant delivered projects of similar type, the named team and their availability, the commissioning and acceptance plan, support and spares after handover, and the total commitment including installation and training rather than the headline equipment figure. Agreeing the weighting in advance also protects the decision from a late intervention by whoever holds the budget.

Comparing proposals that are not alike

The purpose of the exercise is to receive different approaches, which means the offers will not line up in a table. Two supplier routes may differ in automation level, footprint, flexibility and manning, so a straight cost comparison is meaningless without normalising for what each actually delivers. Build a like-for-like view by restating each proposal against the same operating scenario: same output, same product mix, same shift pattern, with the manning, consumables and maintenance each implies. That restatement is where the real differences finally become visible. Ask each supplier to review your restatement of its own offer, since a misread assumption corrected at this point is far cheaper than one discovered during commissioning.

The clarification stage does most of the work

Written proposals rarely settle a decision. Structured clarification sessions, where each supplier presents to the same panel and answers the same core questions, expose whether the proposal was written by the people who would deliver it. Ask how the approach handles a specific awkward variant of your product, what has gone wrong on a comparable installation and what they changed afterwards, and which part of their proposal they consider the highest risk. A supplier unable to name a risk in its own proposal has not thought about it hard enough.

Frequently asked questions

How does a proposal round differ from asking several suppliers for a price?

A price enquiry assumes the solution is defined and asks what it costs. A proposal round assumes the solution is open and asks how each supplier would meet the requirement, with cost following from the approach chosen. The evaluation differs accordingly: you are judging engineering reasoning, delivery history and team credibility, then normalising the commercial offers to a common operating scenario so the figures reflect equivalent outcomes rather than different ones.

Should suppliers be paid for proposal work?

For a substantial engineered proposal involving layout work, simulation or process design, a modest fee to shortlisted suppliers is defensible and often improves what you receive, because it buys real engineering attention rather than sales effort. It also clarifies who owns the resulting concepts. For routine proposals it is unnecessary. The judgement rests on how much genuine design work you are asking a firm to do speculatively, and whether you intend to use the ideas regardless of who wins.

How many suppliers should be invited to propose?

Few, because the effort is heavy on both sides and thin proposals help nobody. Screening candidates first on delivered projects of a similar type, then inviting a small number to propose properly, produces better material than a wide invitation. Each additional invitee reduces the perceived chance of winning, and beyond a small field suppliers begin submitting standard material rather than a considered response to your specific requirement.