How to compare media buying agency proposals: a UK buyer's guide

What to take away

Agree weights and pass or fail checks before any proposal is opened.
Compare agency fee, media cost and technology charges as three separate lines.
Score the legal entity, data handling and exit terms, not just the pitch.
Public sector buyers must follow their own tender timetable and record every step.
Keep one written answer per bidder per question so the audit trail survives.

Set the scoring grid before proposals arrive

Most proposals are written to be hard to compare. Bidders choose different fee models, different media splits and different definitions of reach. A repeatable media buying agency RFP template fixes the sections before the documents arrive, which makes a missing answer visible rather than buried in prose.

The template should open with sections for your objectives, budget range, mandatory pass or fail questions, the scoring grid and the weighting, the data protection questionnaire, the contract and audit terms, and the deadline. Every bidder receives the same version, and no answers are accepted by phone.

Set the scoring grid

Agree criteria and weights with budget holder
Write pass or fail questions first
Issue same brief and template to all
Score alone, then reconcile in one meeting
Tell unsuccessful bidders weightings and scores

The grid itself should be short. Six to ten criteria are enough to separate a strong bid from a well-designed document.

Compare total cost, line by line

Fees quoted as a percentage of media spend can flatter a small budget. Ask every bidder to price the same plan, in the same currency, for the same twelve months. Separate the agency fee from the media cost and the technology charges. Technology charges should name the demand-side platform, the ad server and any data or verification tools, each with its own line.

Compare total cost line by line

Line

Agency fee: Fixed, time or percentage
Media cost: Rate card and discount basis
Technology: Ad server and platform licences
Measurement: Brand lift and attribution charges
Commitments: Minimum spend and notice period

What to ask for

Agency fee: Percentage with no cap
Media cost: Best rates with no evidence
Technology: Unnamed tools billed per impression
Measurement: Costs that grow with campaign
Commitments: Rolling twelve-month minimum

Common red flag

Agency fee
Media cost
Technology
Measurement
Commitments

Line	What to ask for	Common red flag
Agency fee	Fixed fee, time charge or percentage, with VAT treatment stated	Percentage with no cap
Media cost	Rate card, discount basis, principal or agent trading position	"Best rates" with no evidence
Technology	Ad server, demand side platform, verification and reporting licences	Unnamed tools billed per impression
Measurement	Brand lift, attribution and reporting charges	Costs that grow with the campaign
Commitments	Minimum spend, notice period, unused budget rules	Rolling twelve-month minimum

Add a single total to the foot of each column, then compare those totals rather than the headlines. A bid that looks cheap on fee can cost more once minimum commitments and licences are counted.

Before ranking anything, check that each bidder's commercial contract terms survive a budget cut, a change of owner and an early exit.

Transparency checks that separate the bids

Three checks are worth a pass or fail before you look at the total score.

Audit rightsthe contract must let you or your auditor inspect the agency's media records, platform invoices and any principal-based trading. Without it, you cannot verify the numbers.
Rebate and AVB disclosureask how the agency handles volume rebates, agency volume bonuses (AVBs) and any other income from media owners. The answer should be in the contract, not in a verbal promise.
Media ownershipif the agency owns or has an interest in a media owner, a trading desk or an ad tech business, record it. The same disclosure applies to any parent company.

Check the bidding entity, not the pitch deck

The company that signs is the company you can pursue. Look each bidder up on Companies House, then read the filing history, the accounts and any change of name. A polished group website can sit above a dormant contracting entity.

Where two bidders share a parent or a trading desk, record it in the evaluation. The Competition and Markets Authority enforces competition law, including cartel conduct, and two bids that were never independent damage the whole exercise.

Ownership questions also matter where a bidder sits inside a wider group. Ask which entity holds the contracts, which holds the client money and who signs the insertion order.

Where the data protection answers need proof

Sharing audience segments, first party lists or campaign reporting with a shortlisted agency normally makes you a controller. The ICO's UK GDPR guidance and resources set out what you must document, and the Data Protection Act 2018 sits alongside the UK GDPR. Check that the contract includes Article 28 processor terms: the agency must act only on your instructions, keep records of processing, and help you meet your own obligations.

Ask every bidder the same questions: where data is stored, how long it is kept, which sub-processors touch it, and what happens at the end of the contract.

Never send a full customer file to a shortlist for a trial run. Aggregated segments or synthetic data test the method without creating a disclosure you cannot withdraw.

Public sector buyers face a stricter route

If you are a contracting authority, the procurement rules apply from the moment the notice is published. In England, Wales and Northern Ireland the governing rules are the Public Contracts Regulations 2015 and, where they apply, the Procurement Act 2023. Publish the notice on Find a Tender, keep the award criteria in the notice, and observe the standstill period of at least 10 calendar days before awarding. Contracts Finder is used for lower-value and below-threshold notices.

Scotland works to its own procurement legislation, principally the Procurement Reform (Scotland) Act 2014. A cross-border buying team should check which regime governs the contract before drafting questions.

Private buyers can borrow the same discipline. A dated scoring sheet, signed by each panellist, is the evidence that a challenge would test.

Common questions

How many agencies should we shortlist?

Enough to create real competition, few enough that each receives the same brief. A shortlist of three to five keeps the comparison manageable, with one reserve bidder held back.

Should every bidder see the same budget?

Yes, if you want comparable media plans. Give a range and one planning scenario, then ask what each bidder would do at the top and bottom of that range.

Can we score the team on chemistry?

You can, but keep the weight small and define what you are scoring, such as named account leads and how changes are handled. Unexplained gut feel is hard to defend later.

What if a proposal arrives late?

Apply the deadline you published. Note the late arrival, exclude it from scoring and tell the bidder in writing, unless your own rules allow a short extension for everyone.