Before you run a marketing agencies supplier comparison

Treat the comparison as a sequence of decision gates, not a contest between polished presentations. At each gate, decide whether the information is ready to move forward; if not, pause and close the gap. Keep one brief and one assessment record so the final choice can be explained consistently to everyone involved.

If two suppliers could interpret the assignment differently

If potential agencies could understand the work in materially different ways, clarify the request before assessing candidates. Define deliverables, boundaries and expected outputs first. Otherwise, proposals may respond to different questions, leaving the buying team to compare unlike offers rather than deciding which supplier best fits the same brief.

Give every candidate the same written brief and invite responses against that version. The briefing checklist can help make the request specific enough for agencies to work from one shared assignment. Resolve uncertain scope before asking for presentations, since changing the request later can make earlier scores difficult to rely on.

Rule of thumb: Make the assignment clear before comparing suppliers.

If the candidate list includes agencies with uncertain fit

If an agency cannot carry out the defined work, remove it before requesting a proposal.

A long list of weak-fit suppliers adds effort without useful choice, while an overly narrow list can limit the alternatives available for comparison. Keep candidates only where their suitability for this particular assignment can be assessed.

Use the selection checklist to check fit against the brief. Ask each referee what went well and what caused difficulty, then consider that response alongside the proposed work. The shortlist range and reference count shown above are practical comparison guidance, not a substitute for checking whether each agency can meet the requirement.

Rule of thumb: Keep only candidates suited to the same assignment.

If the panel has not agreed how offers will be judged

If assessors would reward different outcomes, settle the criteria and their weights before presentations begin. Give every agency the same assessment and make the weights total 100. Once the process starts, keep the test stable so no supplier is judged against priorities introduced after seeing its proposal.

The retail example gives 25 points each to strategy and the delivery team, 20 each to measurement and fees, and 10 to working style. Treat that split as an illustration, not a default: use the scoring method to set priorities for this brief. If platform capability matters, consider it through software selection.

Rule of thumb: Agree the assessment before suppliers present.

If the quotations describe different payment arrangements

If one proposal uses a monthly retainer and another a project fee, headline totals do not make them comparable. Ask for prices against the same scope, with fee components separated. Payment patterns and commitments can differ even where agencies appear to be offering similar work.

A £4,000 monthly fee with three months' notice creates a different commitment from a £12,000 staged project. Compare retainer fees with possible extra costs. If the arrangement could move from project work to ongoing delivery, the supplier guide can help frame that change.

Rule of thumb: Compare itemised charges for matching work.

If a score cannot be traced to evidence

If an agency makes a broad promise without supporting material, do not give it the same standing as a specific answer backed by evidence. Apply one standard to all candidates, record the source beside each score and keep the working record so another panel member can follow the reasoning.

A compact approach is to mark each criterion from 1 to 5, multiply the mark by its weight, then add the row totals; the quality checklist can help check whether the supporting evidence justifies each mark.

With this method, the maximum is 500. If leading scores are within 20 points, reconsider the weights rather than changing an individual mark; if the result remains tied, request a paid discovery piece from both leading agencies. Retain calculations beside their sources so the written record shows how the decision was reached.

Rule of thumb: Award marks for evidence, not presentation confidence.

If the work involves advertising claims that need approval

If an agency will create advertising claims, ask how those claims are checked, who approves them and where the approval process is recorded. Agree this responsibility during selection, rather than relying on a verbal assurance that leaves no approval record for the panel to inspect.

Use the CAP Code and the Consumer Protection Regulations as references when setting the review requirement. Build time for checking claims into the selection timetable alongside briefing, presentations, references, scoring and negotiation. The tender process can help frame that sequence.

Rule of thumb: Require a recorded route for approving claims.